What are logistics flows? Their types and classification. “Flow and stock as the main categories of logistics

10.10.2019

Test

by discipline

« Logistics »

Option number 3

“Flows in logistics.

Logistics Operations.

Yaroslavl, 2010

I. Flows in logistics…………………………………………………3

1.1. material flow …………………………………… … .4

1.2. Information flow ………………………………… . ..8

1.3. Financial flows …………………………………….….11

1.4. Service flow (service flows) ……………………….…13

II. Logistics operations……………………………………….15

III . Practical part………………………………………… . …17

Task No. 1. Target assignment……………………………….…17

Task number 2. Approximate methods for solving the transport problem…………………………………………………….…19

References………………………………………………………22

I. flows in logistics.

Under flow understand the directed movement of a set of something conditionally homogeneous (for example, products, information, finance, materials, raw materials, etc.). Flows in logistics are one or many objects perceived as a single whole, existing as a process on a certain time interval and measured in absolute units.

Flows in logistics are characterized by such parameters as: the starting point, the final point, the trajectory of the path, the length of the flow and the parameters of their movement (speed, time, intensity, density).

Flows in logistics are classified:

· By degree of continuity (continuous, discrete);

Regularity (deterministic, stochastic);

By stability (stable, unstable);

By variability (stationary, non-stationary);

By the nature of the flow movement (uniform, uneven);

By the degree of periodicity (periodic, non-periodic);

By complexity (simple and complex);

By manageability (managed, unmanaged);

The main flows in logistics are:

· Material flow - goods, goods and materials, details considered in the process of applying various logistics operations to them and related to the time interval;

Information flow - a set of circulating inside logistics system, between it and the external environment, messages needed to manage and control logistics operations;

· Financial flow - the movement of financial resources within the logistics system, between it and the external environment, aimed at achieving the effective movement of a certain material flow;

Service flow is a specific type of activity that satisfies social and personal needs.

1.1. material flow.

A material flow is a product determined in the process of applying various logistics or technological operations to it and related to a certain period of time.

Material flow is a material resource, work in progress, finished products, considered in the process of applying various logistics operations to them (transportation, warehousing, etc.) and related to a certain time interval. The dimension of the material flow is the ratio of the dimension of products (units, tons, m 3, etc.) to the dimension of the time interval (day, month, year, etc.). Material flows can be calculated for specific sections of the enterprise, for the enterprise as a whole , for individual operations with cargo. The material flow, which is considered for a given moment or period of time, becomes inventory(MZ).

The parameters of the material flow can be: nomenclature, assortment, quantity of products, overall, weight, physical and chemical characteristics of the cargo, characteristics of containers, packaging, terms of sale, transportation and insurance, financial characteristics, etc.

The main types of material flows:

external material flow - a material flow flowing in the external environment in relation to the considered logistics system;

internal material flow - a material flow flowing within the considered logistics system;

input material flow - an external material flow entering the logistics system from the external environment;

output material flow - internal material flow coming from the considered logistics system to the external environment;

· cargo flow - the volume of goods transported by certain modes of transport in a certain direction from the point of departure to the destination for a certain period of time (usually considered for a year).

Material flows can be considered as material resources if they have a natural-material composition. With these parameters, material resources are divided into:

raw materials - material resources;

basic materials - materials that are materially included in the manufactured products and make up its material basis (assemblies of parts, assembly units, etc.);

Auxiliary materials - materials used in production, but not constituting the material basis of manufactured products;

semi-finished products - raw materials and materials that have been partially processed in production, but have not yet turned into finished products;

component parts - finished products, which for the buyer are an integral part of the finished product;

detail - a finished part of machines, mechanisms, equipment, which is used in the assembly finished products in producing shops;

assembly - an assembly unit consisting of two or more finished parts and used in the assembly of the finished product.

The specificity of the names of material resources;

Clarity in determining the volume of resources (quantitative characteristics of their mass, volume, area, etc.);

Name of the supplier of material resources and those responsible for the supply and shipment;

Determination of the place of storage of material resources that are subject to transportation;

Indication of the name of the recipient organization of material resources;

Indication of the destination of transportation of material resources;

Determination of the period for the movement of material resources from the storage location at the supplier to the storage location at the recipient.

The intrashop material flow is a flow of material resources that do not move constantly, but with periodic stops at workplace warehouses, at this time the flow does not move, does not change, is not disbanded and is waiting for the processing process.

Intershop material flows are such material flows that, when they enter the input warehouse, are disbanded, and at the output warehouse they are formed into new material flows that move in a certain given direction.

Material flows are distinguished:

1) depending on the nomenclature of elements;

2) by natural-material composition. Defines material flows as single-assortment and multi-assortment;

3) according to the degree of readiness (designed, planned, formed, formed, disbanded, liquidated).

A more detailed classification of material flows is presented in table No. 1.1

Classification of material flows

sign classification	Type of MP	Description
Attitude to drugs and its links	External	Consists of goods related to a particular enterprise, but moving in an environment external to the enterprise
	Interior	It is formed as a result of the execution of a LO with a load inside the LS
	Input	Enters the drug from the external environment
	Day off	Comes from the drug to the external environment
Range	One-way, multi-way
Cargo quantity	Mass	Occurs during the transportation of goods not by a single vehicle, but by a group of them, for example, a train, a convoy of vehicles, a caravan of ships, etc.
	Large	Occurs during the transportation of goods by several wagons, motor vehicles, ships, etc.
	Average	Intermediate between large and small MP (carried by single wagons, cars)
	Small	Occurs when transporting such a quantity of goods that does not allow full use of the carrying capacity of the vehicle and requires combination with other goods during transportation
Specific weight of cargo	Heavy	In the process of its transportation, the full use of the carrying capacity of vehicles is ensured with a smaller volume occupied, for example, metals
Specific weight of cargo	lightweight	It is formed by goods that do not allow full use of the carrying capacity of the transport when its volume is fully used, for example, tobacco products
Degree of compatibility	Incompatible	Such MPs cannot be transported together, for example, goods household chemicals and food
Degree of compatibility	Compatible	Can be transported together on the same vehicle
Cargo consistency	Bulk	It is transported without containers in specialized vehicles: open wagons, on platforms, in containers, in motor vehicles. Their main property is flowability (for example, grain)
	Bulk	Transported without containers, some may freeze, cake, sinter (for example, coal, sand, salt), have flowability
	tare-piece	Cargoes in bags, containers, boxes, without containers, which can be counted
	Bulk	It is transported in tanks and tankers and requires special technical means for reloading, storage and other LP
Nomenclature	Single-product, multi-product
Certainty	deterministic	All parameters are fully known
Certainty	Stochastic	At least one parameter is unknown or is a random variable
Continuity	Continuous	Flows of raw materials and materials in continuous production (technological) processes of a closed cycle, flows of oil products, gas transported by pipelines, etc.
Continuity	Discrete	MPs that are not continuous

1.2. information flow.

The process of managing material flows is based on the processing of information circulating in logistics systems. In this regard, one of key concepts logistics is the concept of information flow.

The information flow is a set of messages circulating in the logistics system between the logistics system and the external environment that are necessary for the management and control of logistics operations. The information flow corresponds to the material flow and can exist in the form of paper and electronic documents.

Logistics information flows through the following five modules:

receiving orders;

processing of orders;

Transportation and cargo handling (shipment);

· distribution;

· Inventory Management.

The main database used for information support of distribution operations consists of the following files:

order data;

data on stocks and warehousing;

Accounting data for receivables;

data on planned distribution requirements.

The control and data entry module is activated when information comes in from outside or when managers make a decision. This usually happens in the following situations:

receiving an order;

Receiving a request about the status of the order;

preparation and coordination of forecasts;

setting the transport tariff;

receipt of goods for storage.

Logistics information flows are characterized by:

Heterogeneity (information used in logistics systems is qualitatively heterogeneous). It should be noted that homogeneity in linear programming and, in particular, in the transport problem is understood as the unlimited possibility of transporting products from any point of departure to any point of destination. With regard to the process of information movement within the logistics system, the requirement for homogeneity also implies an unlimited possibility of transferring any document to any structural subdivision control apparatus;

· plurality of subdivisions - information providers;

· plurality of subdivisions - consumers of information;

the complexity and difficulty of the practical visibility of information routes;

· the multiplicity of the number of transfers of documentation units for each route;

· multivariate optimization of information flows.

Methodologically important from the point of view of logistics is the definition of the interaction of material and information flows. It has always been believed that the material flow generates information flow, i.e., the primacy of the material flow was postulated. However, modern information technologies have changed the sequence of interaction between material and information flows, and currently there are three options for their interaction.

1. The information flow is ahead of the material flow. In this case, the information flow receives information about the achievement of material flows (forward direction) or it contains information about the order (opposite direction).

2. Information accompanies the material flow, moves simultaneously with it. This stream contains information about the quantitative and qualitative parameters of material flows, which allows you to correctly and quickly assess their condition and make the necessary regulatory decisions.

3. Information flow lags behind material flows. In this case, the information serves only to evaluate the results.

The increasing role of information flows in modern logistics is due to the following main reasons:

- for the consumer, information about the status of the order, the availability of goods, delivery times, shipping documents, etc. is a necessary element of consumer logistics service;

- from the position of inventory management in the supply chain, the availability of complete and reliable information can reduce the need for inventory and workforce by reducing the uncertainty of demand;

- information increases the flexibility of the logistics system regarding how, where and when resources can be used to achieve competitive advantages.

The main types of information flows are presented in table No. 1.2.

Classification of information flows

Classification sign	Type of information flow
Attitude to drugs and its links	Internal, external, horizontal, vertical, inlet, outlet
Type of storage media	On paper, on magnetic media, optical, digital, electronic
Frequency of use	Regular, periodic, operational
Purpose of information	Directive (management), normative and reference, accounting and analytical, auxiliary
Degree of openness	open, closed, secret
Data transfer method	By courier, mail, telephone, telegraph, teletype, email, fax, telecommunication networks
Communication mode	on-line, off-line
Orientation relative to MP	In the forward direction with MP, in the opposite direction with MP
Synchronicity with MP	Leading, simultaneous, subsequent

1.3. financial flows.

The financial flow is a set of financial resources circulating in the logistics system, between the logistics system and the external environment, associated with material and information flows. The movement of financial flows can take place both inside the logistics system and outside it. Thus, the specificity of financial flows in logistics lies precisely in the need to service the process of movement in space and time of the corresponding flow of inventory or inventory items.

The market economy, with all the variety of its models, is characterized as a socially oriented economy, which implies mandatory state regulation. Finance plays a huge role in the structure of market relations. Financial flows revolve in the financial environment. The financial environment means the internal and external environment of the enterprise, finances and financial resources (financial flows), sources and consumers of resources.

Financial relations cover relations related to education and the movement of financial resources between:

1) the state and the enterprise (enterprises);

2) between the enterprises themselves;

3) between individual states.

The financial institutions of the state include: the Ministry of Finance, its bodies, local financial departments and departments, financial departments of enterprises and control and audit departments. The financial system includes the following links: state and local budgets, social insurance funds, pension funds, personal and property insurance funds, finances of enterprises, industries, various special monetary funds. The financial flow depends on the availability of a serviced commodity flow. The direction of the movement of financial flows in logistics is determined by the need to ensure the movement of the corresponding material flow. In addition, the size and time of the movement of the financial flow (including the time of the beginning of the movement) depend on the chosen form of settlement between the seller and the buyer. At the same time, the form of mutual settlements with securities is considered the most effective. The movement of financial resources is necessarily accompanied by the corresponding documents, on the basis of which financial transactions are carried out. The emergence of financial flows, direction and movement depend on the conditions specified in the sales contract (calculations of the supplier-buyer), the basic terms of delivery.

One of the possible classifications of financial flows is shown in Table 1.3.

Classification of financial flows

Classification sign	Type of financial flow
Attitude to drugs and its links	Internal, external, input, output
Purpose	Conditioned by the procurement process, investment, labor reproduction, the formation of material costs in the production process, determined by the process of selling products
Method of transferring the advanced value to goods	Associated with the movement of fixed assets, due to the movement working capital
Type of economic relations	Horizontal, vertical
Calculation form	Cash (cash), information and financial (non-cash), accounting and financial (when forming material costs in the production process)

1.4. Service flow (service flows)

In addition to the material, informational and financial type of flows, there are also service flow, representing the number of services provided for a certain time interval. Under service refers to a special type of activity that satisfies public and personal needs (transport services, wholesale and retail, consulting, information, etc.). Services can be provided by people and equipment in the presence of customers and in their absence, to meet personal needs or the needs of organizations. The need to introduce the concept of service flow is due to the growing importance and development of the service industry and the concentration of an increasing number of companies and people in it.

Service flows - flows of services (non-material activity, a special type of product or product) generated by the logistics system as a whole or its subsystem (link, element) in order to satisfy external or internal consumers of the business organization.

Service - the process of providing a service - the activities of the supplier necessary to provide the service.

The importance of logistics services has been especially increasing recently, which is explained by many reasons. Among them are social programs adopted by the governments of various countries, the development of the service industry and the concentration in it of an increasing number of companies and the employed working population, the focus of many firms on the end user, the development of the concept of total quality management in the service industry.

Despite the importance of the service, effective ways there are still no assessments of its quality, which is explained by a number of features of the service in comparison with the characteristics of the products. Such features (characteristics of service flows) are:

1. Intangibility of the service. It consists in the difficulty for service providers to explain and specify the service, as well as the difficulty in assessing it on the part of the buyer.

2. The buyer often takes a direct part in the production of services.

3. Services are consumed at the time of their production, i.e. services are not stored or transported.

4. The buyer never becomes the owner of the service.

5. Service is an activity (process) and therefore cannot be tested before the customer buys it.

6. A service often consists of a system of smaller (sub-services) services, with the customer evaluating these sub-services.

These characteristics and features of service flows play an important role in the logistics process.

II. logistics operations.

The logistics operation is independent part logistics process performed at one workplace and (or) using one technical device; a separate set of actions aimed at transforming the material and (or) information flow.

Logistics operations can be classified into:

External - aimed at the implementation of the functions of supply and marketing;

internal - carried out within the framework of the implementation of the production function;

basic - these include: supply, production and marketing;

Key logistic operations are subdivided into: maintenance of customer service standards; procurement management; transportation; Inventory Management; management of order procedures; management of production procedures; pricing; physical distribution;

supporting logistics operations are divided into: warehousing; cargo handling; protective packaging; ensuring the return of goods; provision of spare parts and service; information and computer support.

Logistics operations with material flows in the sphere of circulation are operations of loading, unloading, transportation, picking, warehousing, distribution, packing.

Logistics operations with material flows in the field of production are reduced to placing orders, managing warehousing, selecting equipment, producers and suppliers, planning and scheduling the production process, accounting and inventory management.

Logistical operations with information flows are reduced to the creation of information systems and the implementation within these systems of actions to collect, store, process and transfer information accompanying material flows and initiating and managing these flows. The costs of performing logistics operations with information flows constitute a significant part of logistics costs.

Some logistics operations are, in essence, a continuation of the technological production process, for example, packaging. These operations change the consumer properties of the goods and can be carried out both in the sphere of production and in the sphere of circulation, for example, in the packaging shop of the wholesale base.

Logistics operations performed in the process of supplying an enterprise or marketing finished products are classified as external logistics operations. Logistics operations performed within the logistics system are called internal. Uncertainty environment primarily affects the nature of the implementation of external logistics operations.

One of the possible classifications of financial flows is shown in Table No. 2.1

Classification of logistics operations

III. Practical part.

Task #1

Destination task

Given: A B C D E - objects of work,

1 2 3 4 5 - brigades.

It is necessary to define five work teams for five jobs so that the total duration of the work is minimal.

1. Let's reduce the matrix by rows. In each line we find the minimum element and subtract its value from all cells of the line.

I	A	B	C	D	E	α i	II	A	B	C	D	E
1	5	7	14	5	7	5	1	0	2	9	0	2
2	8	10	6	3	-	3	2	5	7	3	0	-
3	4	-	4	8	10	4	3	0	-	0	4	6
4	11	9	5	9	12	5	4	6	4	0	4	7
5	1	6	2	8	6	1	5	0	5	1	7	5

2. Similarly, we present the matrix by columns.

III	A	B	C	D	E	IV	A	B	C	D	E
1	0	2	9	0	2	1	0	0	9	0	0
2	5	7	3	0	-	2	5	5	3	0	-
3	0	-	0	4	6	3	0	-	0	4	4
4	6	4	0	4	7	4	6	2	0	4	5
5	0	5	1	7	5	5	0	3	1	7	3

β j 0 2 0 0 2

Let's determine the preliminary costs of the work. For this we use the formula:

T=∑ α i +∑ β j

i =1 j =1

Thus, the preliminary costs of the work will be: T \u003d 18 + 4 \u003d 22

3. Let's place the rooks in cells with zeros (a rook should not "hit" another rook). In our case, (matrix IV), it is not possible to place the rooks.

4. If we draw the minimum number of intersecting lines through all zeros, then we get an equivalent transformation.

V	A	B	C	D	E
1	0	0	9	0	0
2	5	5	3	0	-
3	0	-	0	4	4
4	6	2	0	4	5
5	0	3	1	7	3

Among open cells, the minimum element (Delta) is searched, in this case ∆ 1 =2.

The value of the minimum element is added to the total work:

T 1 \u003d 22 + 2 \u003d 24

The value of ∆ is subtracted from open cells, added to the cells that lie at the intersection, the rest remain unchanged.

If we return to the matrix considered in paragraph 3, then in this case it turns out to place the rooks.

VI	A	B	C	D	E
1	2	0	11	2	0
2	5	3	3	0	-
3	0	-	0	6	2
4	6	0	0	4	3
5	0	1	1	7	1

Thus, we can conclude that the most minimal labor costs for the total duration of work will be the teams:

A-5, B-4, C-3, D-2, E-1. At the same time, the total labor costs of performing the work amounted to 24 days.

If you look at matrix I and select cells according to our work plan, you will see that 1+9+4+3+7=24. Accordingly, the problem is solved correctly.

Task number 2.

Approximate methods for solving the transport problem.

1 method: "Northwest corner".

According to this method of filling in the attachment table, one should start from the upper left square and compare resources and needs from the position of this square. Choose a smaller value from them and write it into this square, which from that moment on becomes “loaded”.

Transportation is carried out through cell 1/1, choosing a minimum of what is and what is needed. Next, we look, if all the goods are exported from the point of departure, then the line is closed and we consider the cell below. If, however, the need for a destination is fully satisfied, then close the column and move to the cell to the right.

j	1	2	3	4
i	bj	12	20	10	13
a i
1	15	16	15	12	7
12	3
2	5	9	22	5	10
5
3	17	17	7	8	4
12	5
4	5	10	14	4	12
5
5	13	16	15	11	18
13

To determine the transport costs, we use the formula:

С = ∑ ∑ C ij X ij →min

Thus, the transport costs will be:

C1 \u003d 16 * 12 + 15 * 3 + 22 * 5 + 7 * 12 + 8 * 5 + 4 * 5 + 18 * 13 \u003d 725

Method 2: "Minimum per line".

In the line, the minimum cost is searched, and transportation is carried out through this cell. If the line is open, then we look for the next cell with the minimum cost. After the line is closed, go to the next line.

j	1	2	3	4
i	bj	12	20	10	13
a i
1	16	15	12	7
15	2	13
2	9	22	5	10
5	5
3	17	7	8	4
17	17
4	10	14	4	12
5	2	3
5	16	15	11	18
13	10	3

Using the formula for determining transportation costs, we get:

С = ∑ ∑ C ij X ij →min

С2 = 12*2+7*13+5*5+7*17+10*2+4*3+16*10+15*3 = 496

Method 3: "Minimum by column".

In this case, consider a column. We are looking for the minimum cost in it and carry out transportation. If the column is not closed, then we look for the next minimum element, and if it is closed, then we go to the next column.

j	1	2	3	4
i	bj	12	20	10	13
a i
1	15	16	15	12	7
2	3	10
2	5	9	22	5	10
5
3	17	17	7	8	4
17
4	5	10	14	4	12
5
5	13	16	15	11	18
10	3

Similarly, we determine transport costs, in this case С3=525

Method 4: "Minimum element method"

This method provides: in the matrix, the minimum element through which the transportation is carried out is selected. Next, rows or columns are closed, if possible. The minimum element is searched among open cells, etc.

j	1	2	3	4
i	bj	12	20	10	13
a i
1	15	16	15	12	7
15
2	5	9	22	5	10
5
3	17	17	7	8	4
4	13
4	5	10	14	4	12
5
5	13	16	15	11	18
12	1

Similarly, we determine transport costs, in this case С4=557

Thus, we can conclude that the minimum cost of transportation is obtained by the second method "Minimum per line". It is equal to 496.

Bibliography

1. Alesinskaya T.V. Fundamentals of logistics. General issues of logistics management: Proc. allowance. - Taganrog., Publishing House of TRTU, 2005

2. Gadzhinsky A.M. Logistics: Ed.4th. - M.: Marketing, 2001

3. Logistics: Textbook / Ed. B. A. Anikina. - M.: INFRA - M, 2000.

4. Nerush. Yu.M., Logistics: Textbook for universities. - 3rd ed., revised. And extra. - M.: UNITI-DANA, 2003. - 495 p.

5. Fundamentals of logistics: Proc. allowance / ed. L.B. Mirotin and V.I. Sergeyev. - M.: INFRA - M, 2002

6. Sarkisov S.V. Logistics management. - M., 2004

Gadzhinsky A.M. Logistics: Ed.4th. - M.: Marketing, 2001

Alesinskaya T.V. Fundamentals of logistics. General issues of logistics management: Proc. allowance. - Taganrog., Publishing House of TRTU, 2005

The object of study of logistics as a science and the object of logistics management as a business area is a system of material, information, financial and other flows. The fundamental difference between the logistic approach and the previous control of the movement of material resources was that if earlier the object of control was a certain accumulation of individual material objects, then with the logistic approach, the main object was the flow, i.e. a set of objects perceived as a single whole.

Flow is a collection of objects, perceived as a single whole, existing as a process at a certain time interval and measured in absolute units for a certain period. Flow parameters are parameters that characterize the number of objects that are available at a particular point in time and are measured in absolute units. The main parameters characterizing the flow are: its initial and final points, the trajectory of movement, the length of the path, the speed and time of movement, intermediate points, intensity.

Flows are classified on the following grounds:

1. For the system in question:

a) internal flows - circulate within the system;

b) external flows - are outside the system;

c) incoming flows are external flows coming from the external environment into the logistics system;

d) outflows are internal flows, according to
stepping from the logistics system into the external environment.

2. By degree of continuity:

a) continuous flows - at each moment of time, a certain number of objects move along the trajectory of the flow;

b) discrete flows - are formed by objects moving at intervals;

3. According to the degree of regularity:

a) deterministic flows - characterized by the certainty of the parameters at each point in time;

b) stochastic flows - are characterized by the random nature of the parameters, which at each moment of time take a certain value with a known degree of probability.

4. According to the degree of stability:

a) stable flows - characterized by the constancy of the values of the parameters for a certain period of time;

b) unstable flows - characterized by changes in flow parameters.

5. According to the degree of variability:

a) stationary flows - characteristic of a steady process, their intensity is a constant value;

b) unsteady flows - characteristic of an unsteady process, their intensity varies over a certain period.

6. By the nature of the movement of flow elements:

a) uniform flows - are characterized by a constant speed of movement of objects: in the same periods of time, objects pass the same path, the intervals for the beginning and end of the movement of objects are also equal;

b) uneven flows - characterized by a change in the speed of movement, the possibility of acceleration, deceleration, stops along the way, changes in the intervals of departure and arrival.

7. According to the degree of frequency:

a) periodic flows - characterized by the constancy of parameters or the constancy of the nature of their change after a certain period;

b) non-periodic flows - are characterized by the absence of a regularity in the change in flow parameters.

8. According to the degree of compliance of changes in flow parameters with a predetermined rhythm:

a) rhythmic flows;

b) non-rhythmic flows.

9. By degree of difficulty:

a) simple (differentiated) flows - consist of objects of the same type;

b) complex (integrated) flows - unite heterogeneous objects.

10. By degree of control:

a) controlled flows - adequately responding to the control action from the control system;

b) uncontrolled flows - not responding to the control action.

By the nature of the generating objects, the following types of flows can be distinguished: material, transport, energy, Money, informational, human, military, etc., however, for the logistics of the economic sphere, material, informational and financial flows are of the greatest interest.

2. CHARACTERISTICS OF THE MAIN FLOWS IN THE ENTERPRISE

2.1. materialistic flows

A material flow is a product (in the form of cargo, parts, inventory items) considered in the process of applying to it various logistics (transportation, warehousing, etc.) and / or technological (machining, assembly, etc.) operations and assigned to a certain time interval.

The material flow, considered not at a time interval, but at a given point in time, is a material reserve.

Material flows in logistics are characterized by the following parameters:

nomenclature, range and quantity of products;

overall characteristics (total mass, area, linear parameters);

weight characteristics (total weight, gross and net weight);

physical and chemical characteristics of the cargo;

characteristics of the container or packaging, vehicle (carrying capacity, cargo capacity);

terms of the contract of sale (transfer of ownership, supply);

conditions of transportation and insurance;

financial (value) characteristics;

conditions for performing other physical distribution operations related to the movement of products;

and etc.

Quantitatively, the material flow is expressed by such indicators as intensity, density, speed, etc.

The following features of the classification of material flows are distinguished:

1. In relation to the logistics system, internal (not going beyond the logistics system) flows and external flows entering the logistics system from the external environment (input) and leaving the logistics system into the external environment (outputs) are distinguished.

2. In relation to the link of the logistics system, material flows are divided into input and output.

3. According to the nomenclature, material flows are divided into single-product (single-type) and multi-product (multi-type). In this case, the nomenclature is understood as a systematized list of groups, subgroups and positions (types) of products in physical terms (pieces, tons, m3, etc.). It is mainly used for statistical reporting, accounting and planning.

4. According to the assortment, material flows are divided into single-assortment and multi-assortment. At the same time, the assortment is understood as the composition and ratio of products of a certain type or name, differing from each other in grade, types, sizes, brands, exterior finish and other features.

5. In the process of transportation, goods are classified according to the type of transport, method and conditions of transportation, overall, weight and physical and chemical characteristics of the cargo, methods of packing, etc.

A mass flow is a flow that requires transportation by a group of vehicles, for example, an entire train of many cars, a column of trailers, etc.

A large traffic is a traffic that requires several wagons or trailers, etc.

Medium traffic is the traffic formed by single wagons, trailers, etc.

A shallow stream is a stream of goods that is smaller than the carrying capacity of a single vehicle and can be combined with other small streams during transportation.

Heavyweight flows are flows formed by high-density loads and, therefore, occupying a smaller volume for the same weight. This includes flows formed by cargoes with a mass of one piece for water transportation of more than 1 ton, and for rail transportation - 0.5 tons.

Lightweight flows are flows formed by goods with low density, and therefore, with a given volume, determined by the dimensions allowed for a given vehicle, having a low weight. In such flows, 1 ton of cargo occupies more than 2 m3.

Oversized flows are flows of goods, the height of one place of which is more than 3.8 m, the width is more than 2.5 m, and the length is greater than the length of the cargo area.

6. According to the degree of determinism of the flow parameters, deterministic and stochastic material flows are distinguished. A flow with completely known (deterministic) parameters is called deterministic. If at least one parameter is unknown or is a random variable (process), then the material flow is called stochastic.

7. By the nature of movement in time, continuous and discrete material flows are distinguished. The former include, for example, the flows of raw materials and materials in continuous production (technological) processes of a closed cycle, the flows of oil products and gas transported by pipelines, etc. Most of the flows are discrete in time.

2.2. Financial flows

In the process of moving from one economic entity to another, a set of certain commodity values \u200b\u200bcan be considered as an appropriate commodity flow, the movement of which is due to the performance of a number of logistics operations.

In a market economy, increasing the efficiency of the movement of commodity flows is achieved mainly by improving their financial services. This, in turn, necessitates the identification and study of logistical financial flows corresponding to the movement of commodity values: all types of material goods, services, capital and intangible assets.

Financial flow is a directed movement of financial resources associated with material, information and other flows both within the logistics system and outside it.

Financial flows arise when recovering logistics costs and expenses, raising funds from funding sources, reimbursing (in monetary terms) for products sold and services rendered to participants in the logistics chain.

The mechanism of financial service of commodity flows is currently the least studied area of logistics.

Financial flows in one form or another have always existed in any way of organizing business activities. However, as practice has shown, the greatest efficiency of their movement is achieved by applying the logistical principles of managing material and financial resources, which led to the emergence of a new economic category - the logistical financial flow. Consequently, logistical financial flows are created and used to ensure the efficient movement of commodity flows. At the same time, the specificity lies primarily in the need to service the process of movement in space and time of the corresponding flow of commodity-material or commodity-intangible assets.

Logistic financial flows are heterogeneous in their composition, direction of movement, purpose and other characteristics, which necessitates their classification. In each specific case, it is necessary to establish its own, special composition of the classification features of logistics financial flows. To classify financial flows in logistics, mainly such features as attitude to the logistics system, purpose, method of transferring the advanced cost, form of calculation, type of economic relations are used.

In relation to a specific logistics system, external and internal financial flows are distinguished.

The external financial flow flows in the external environment, i.e., outside the boundaries of the logistics system under consideration, the internal one exists within the logistics system and is modified by performing a number of logistics operations with the corresponding commodity flow. In turn, external logistics financial flows in the direction of movement are divided into:

incoming financial flow (enters the considered logistics system from the external environment);

outgoing financial flow (starts its movement from the considered logistics system and continues to exist in the external environment).

By purpose, logistics financial flows can be divided into the following groups:

financial flows due to the process of purchasing goods;

investment financial flows;

financial flows for the reproduction of labor force;

financial flows associated with the formation of material costs in the process of production activities of enterprises;

financial flows arising in the process of selling goods.

According to the method of transferring the advanced value to goods, logistical financial flows are divided into financial resource flows:

accompanying the movement of fixed assets of the enterprise (this includes investment financial flows and partially financial flows associated with the formation of material costs);

due to the movement of working capital of the enterprise (financial flows arising in the process of purchasing, distributing and selling goods, as well as in the reproduction of labor force).

Depending on the forms of payment used, all financial flows in logistics can be differentiated into two large groups:

monetary - characterizing the movement of cash;

information and financial - due to the movement of non-cash financial resources.

In turn, cash financial flows are divided into flows of cash financial resources for settlements in rubles and for settlements in foreign currency, and information and financial flows include flows of non-cash financial resources for settlements by payment orders, payment requests, collection orders, documentary letters of credit and settlement checks.

According to the types of economic relations, horizontal and vertical financial flows are distinguished. The former reflect the movement of financial resources between equal business entities, the latter - between subsidiaries and parent commercial organizations.

The main purpose of the financial service of commodity flows in logistics is to ensure their movement with financial resources in required volumes, at the right time, using the most efficient sources of funding. In the simplest case, each commodity flow has its own unique financial flow.

The parameters of financial flows serve as indicators of the well-being and sustainability of enterprises, testify to the effectiveness logistics activities, they are necessary when planning and organizing relationships with contractors. For example, when drawing up the budget for the current year, they predict the amount of upcoming revenues and necessary investments, calculate the profitability and profitability indicators that are necessary when preparing financial statements, justifying the attraction of investments and loans, concluding contracts and agreements.

Financial parameters largely determine the economic viability of enterprises, their stability in the market, the strength of relationships with suppliers and consumers.

2.3. Information flows

The information flow is a flow of messages in speech, documentary (paper and electronic) and other forms, accompanying the material or service flow in the considered logistics system and intended mainly for the implementation of control actions.

Information flows arising from external influences on the corresponding environment transfer information (messages) from its sources to its consumers. These flows can be of great independent importance for operational management and the development of strategic decisions, or they can correspond to material ones and manage them. The difference in the speeds of material and information flows can, if there is a correspondence, lead to a time shift between them.

To process information flows, modern logistics systems incorporate an information logistics center. The task of such a center is the accumulation of received data and their pragmatic filtering, i.e., turning it into information necessary for solving logistical problems. At the same time, the connection of the center with information sources can be one-way, two-way and multilateral. Modern logistics systems use the latter method of communication.

Thus, logistics operates with numerous indicators and characteristics of information flows: the nomenclature of transmitted messages, data types, documents, data arrays; the intensity and speed of data transfer; special characteristics (bandwidth of information channels, protection against unauthorized access, noise immunity, etc.).

There is no isomorphism between the information and material flow (i.e., one-to-one correspondence, synchronism in the time of occurrence). As a rule, the information flow either outstrips the material flow or lags behind it. In particular, the very origin of the material flow is usually a consequence of information flows during, for example, negotiations on transactions for the sale of goods, drafting contracts, etc. The presence of several information flows accompanying the material flow is typical.

Information flows in logistics are formed in the form of streams of electronic data arrays, paper documents in a certain way, as well as in the form of flows consisting of both of these types of information quanta.

Such information includes:

telephone messages and faxes;

waybills coming with the goods;

information on the receipt and placement of goods in warehouses;

data on transport tariffs and on possible routes and types of transport;

changes in dynamic models of the state of stocks;

control program libraries for technological equipment with numerical control and catalogs of these libraries;

various regulatory and reference production information;

changes in dynamic models of the market and in its segmentation;

current information about production capacities;

current information about suppliers and producers;

changes in dynamic models of the portfolio of orders;

current information about work in progress;

data on release plans;

current data on warehouses;

data on volumes and types of finished products;

data on the actual sale of products to consumers;

data on financial flows.

Thus, the information created, stored, circulating and used in the logistics system can be considered useful if it is possible to include it in the current production and marketing processes.

For the successful and efficient implementation of logistics management based on the analysis of information flows, certain factors and prerequisites are required, namely:

availability of relevant information characteristics of the process;

an adequate level of systematization and formalization of the logistics management process;

organizational forms and system of methods of logistics management;

the possibility of reducing the duration of transient processes and prompt feedback on the results of logistics activities.

The information flow is defined by the following parameters:

1. Source of occurrence.

3. The rate of transmission, i.e. the amount of information transmitted per unit of time.

4. The total volume, i.e., the total amount of information that forms this stream.

The information flow can function in the same direction as the corresponding material flow, or it can be directed towards "its own" material flow. The direction of the information flow may in some cases have nothing to do with the direction of movement of the corresponding material flow. For example, components come from the producer to the input warehouse, and the corresponding accounts go to the accounting department.

If orders for the supply of raw materials, materials and components are satisfied, the information flow formed by these orders, issued in the form of documents, is directed in the direction opposite to the corresponding material flow. It arises before this material flow. In other words, this information flow precedes the material flow initiated by it.

The information flow moving towards the material can be not only preliminary, as already described above, but also lagging behind. For example, the flow of information formed by documents on the results of acceptance or refusal to accept cargo, various claims, warranty documents, etc.

Thus, information flows can lead, lag behind or be synchronous with the corresponding material flows. Each of these types of information flows can move in the same direction as the corresponding material flow, be opposite to it, or move in a direction that does not coincide with it.

Each type of information flow is characterized by its combination of these two qualities. Accordingly, the following types of information flows can be named:

leading with the same direction;

leading counter;

leading, differing in direction;

synchronous with the same direction;

synchronous counter;

synchronous, differing in direction;

lagging behind with the same direction;

lagging counter;

lagging behind, differing in direction.

Thus, various information flows are the links that unite various functional subsystems into a single whole. In each of these functional subsystems, material flows are realized that correspond to the goals provided by these subsystems. Information flows unite these subsystems into a single whole, so that the individual goals of each subsystem are subject to the overall goal of the entire value chain. This is the basic concept of logistics.

The types of information flows circulating in logistics systems have some difference from all other types of flows. The difference lies in the very object of movement - the exchange of information between different parts of the logistics system.

2.4. Service flows

Service flows are flows of services (non-material activity, a special type of product or product) generated by the logistics system as a whole or its subsystem (link, element) in order to satisfy external or internal consumers of the business organization.

Service - the process of providing a service - the activities of the supplier necessary to provide the service.

A large number of links in the logistics system and logistics intermediaries are service enterprises in which services are inextricably linked with a product that is distributed, promoted to the market and sold at different parts of the logistics chain. These links include various transport companies, wholesalers and retailers, distribution companies, etc. At the same time, the cost of services can significantly exceed the direct costs of manufacturing products.

In the West, the concept of "service response logistics" - SRL, is widely used, which is defined as the process of coordinating the logistics operations necessary to provide services in the most cost-effective way and satisfy customer needs.

The SRL approach is often the main strategic element in the management of many foreign service firms. Critical elements of this approach are the receipt of orders for services and the monitoring of service delivery. Like material flows, service flows are distributed in a specific delivery environment (for finished products - in the distribution network), which has its own links in the logistics system, logistics channels, chains, etc. This network should be built in such a way that with maximum efficiently meet customer service requirements. Networks of stations can serve as examples of such networks. Maintenance and service points of automotive companies, pre-sales and after-sales service networks of most companies producing industrial electrical household goods, etc.

Until now, there are no effective ways to assess the quality of service services, which is explained by their features in comparison with product characteristics. Such features (characteristics of service flows) are:

1. The complexity of the specification of services by the service firm and their evaluation by the buyer.

2. The buyer may be a direct participant in the process of providing services.

3. Services are consumed at the same moment they are provided, i.e. they cannot be stored or transported.

4. The buyer, purchasing services, never becomes their owner.

5. The quality of the service cannot be tested until the buyer pays for it.

6. The provision of services often consists of a system of smaller (sub-service) activities, with the buyer evaluating all of these activities.

These characteristics and features of services play an important role in the logistics process.

The evaluation of the quality of services in the analysis and design of logistics systems should be based on the criteria used by the buyers of services for these purposes.

For each parameter for assessing the quality of services, there are two values (conditional) - expected by the buyer and actual. The difference between these two values is called the discrepancy (mismatch) and assesses the degree of satisfaction of the buyer with the quality of the service. In Western economic literature, this discrepancy is often referred to as the gap.

To rationalize logistics management in the channels of promotion and sales of goods, it is necessary: firstly, to correctly assess the parameters of service quality, and secondly, to build management in such a way as to minimize the discrepancy between the expected and actual levels of service quality.

To do this, various assessment methods are used, such as, for example, customer questionnaires, expert assessments, statistical methods, etc. The difficulty lies in the fact that most service quality parameters cannot be measured quantitatively, i.e., a formalized assessment can not be obtained.

Material flow is the basic object of research, management and optimization in logistics. It represents the movement of inventory items both within the enterprise and outside it.

Logistics of material flows is a way of organizing and managing a process at any stage of production in order to ensure maximum profit.

Types of logistics material flows

There are several classifications of such a turnover of valuable goods. The first is characterized by the attitude to the logistics system. It includes three types of flow:

input;
day off;
interior;
external.

The first is the flow that entered the logistics system from the external environment. It is determined by the following formula: the sum of the values of material flows divided by unloading operations.

The output material flow, on the contrary, enters the external environment from the enterprise. To determine its indicator, it is necessary to add up the number of goods shipped to points of sale and to wholesale warehouses.

The internal flow is formed as a result of performing certain operations with a shipment within a manufacturing organization or logistics system. External material flow is related to the activities of the organization, as well as points of sale of products or subsidiaries.

Classification of the material flow by nomenclature and assortment

This characteristic is important for enterprises with any product range. The material flow can be single-product and multi-product. The first type refers to products of one type, the second - to a wide variety of goods.

By assortment, flows are classified as single-assortment and multi-assortment. They differ from each other in the amount of incoming or outgoing products.

Classification of material flows according to physical and chemical properties

Bulk cargoes are cargoes of mineral or mountain origin. These include sand, ore, coal, natural agglomerates and much more.

Bulk cargo - products that are transported without containers. These are grains and cereals, as well as other similar products.

Liquid cargoes are transported in tanks, tankers. The process of shipment and transportation is impossible without special technical means.

Packaged cargo - products have different physical and chemical properties and parameters. It is transported in containers, bags, boxes, without containers.

Other material flow classifications

A variety of classifiers for the movement of inventory items helps to keep accounting records correctly.

Material logistics flows are divided according to the following criteria:

On a quantitative basis. Bulk - appears when a large batch of products is shipped. Small - shipment of small consignments of goods with a minimum vehicle load. Large - shipment of goods is carried out by several wagons or cars. Medium - goods that come from transportation by small cars or single wagons.
By specific weight. Lightweight flows do not make it possible to fully use the carrying capacity of the vehicle. For heavy vehicles, the permissible load capacity of the vehicle is used for transportation.
According to the degree of compatibility. Compatibility and incompatibility of goods during transportation, processing and storage are taken into account.

The correct organization of material flows is based on the latest classification. Let's take an example. It is necessary to deliver dairy products from the warehouse to retail outlets. Along with it, confectionery products will be shipped. The conditions and shelf life of such products are different. This means that they cannot be loaded into one vehicle.

material flows

There are several factors that affect the correct planning of shipments of goods. The material flow of any type corresponds to the information flow.

The material flow management system is based on such basic principles: general logistics and specific. They, in turn, are classified as follows:

System approach - used when considering the elements of the logistics system. The goal is to optimize material flow and maximize profit.
The principle of total costs - keeping records of material and information flows. The task is to identify the costs of managing the logistics system.
The principle of global optimization is the optimization and management of material flows as a result of the coordination of local chains.
The principle of the theory of trade-offs for the redistribution of costs is the correct organization between all elements of the system.
The principle of complexity. Used to create and optimize
coordination and integration. This is the achievement of normal functioning between all participants in the logistics system on manufacturing plant.
The principle of total quality management. It ensures the reliability and stability of each element of the logistics system.
The principle of modeling is used to create, analyze, organize logistics processes in various chains of the system.
The principle of stability and adaptability. The logistics system must function stably. Having studied the influence of negative factors, it is possible to establish logistics at any enterprise.
The principle of integrity is to ensure information cooperation between all parts of the system.

The material flow system is based on these ten principles. To ensure its normal operation, it is necessary to use other indicators and characteristics of the logistics system.

Materials management

Stable operation of a manufacturing enterprise is impossible without well-established logistics. There are two methods of material flow management: push and flow systems.

The first method assumes that the production of products begins, is carried out and ends at the same stages of the production line, depending on the logistics system. Every action is coordinated. The transfer of goods occurs on command from a specific control center. The site has a specific plan and production indicators. All elements of the system function separately, but are interconnected.

The current system is characterized by the fact that all funds (raw materials, materials, finished products, etc.) arrive at the site as needed. There is no centralized control in this system. It contributes to a significant reduction in inventories, since the movement of material flows passes through only a few elements of the logistics system.

Example of a push system for logistics material flows

This is how the approximate traffic pattern looks like: production - packaging - shipment.

As a rule, in a large-scale manufacturing enterprise, the material flow process includes more than 10 elements:

workshop for the procurement of raw materials;
shop for its processing;
production shops of various types;
supervisory authority;
management shop;
packing link and so on.

It all depends on the type of product being manufactured, as well as its characteristics.

The main object of research, management and optimization in logistics is the material flow.
Material flows are formed as a result of transportation, storage and other material operations with raw materials, semi-finished products and finished products, starting from the primary source, raw materials and up to the end consumer. The material flow is called goods, parts, inventory items, considered in the process of applying various logistics operations to them and related to the time interval.
Material flow - products that include various products, parts, inventory items, considered in the process of applying various technological operations to it (loading, transportation, unloading, processing, sorting, storage, etc.) and assigned to a specific time interval (Fig. 1).
Also, material flows can be defined as various types of products that are in a state of motion (material resources, work in progress, manufactured products), to which logistical actions are applied related to physical movement in space and time (loading, unloading, processing, storage, sorting, etc.). .P.). If the product is not in a state of movement, but is in a waiting position, then it belongs to the stock.

Rice. 31. The structure of the material flow
Material resources include objects of labor: raw materials, basic and auxiliary materials, semi-finished products, components, fuel, spare parts, production waste. Work in progress - products that are unfinished by production within a given organization (enterprise), which tend to accumulate or linger in production, "adapters" (i.e. between workshops or sites). Finished products - products that have passed the full technological (production) cycle in this organization, fully equipped, handed over to the warehouse of finished products or shipped to the consumer (Fig. 2).

Rice. 2. Product status structure
The task of the logistician is to achieve the optimum values of the logistics flow both in the process of its movement (optimal production volume) and in the state of stock (optimal volume of products in stock). The optimization of the flow in the process of movement concerns the values of costs and time (production or commercial cycle). Costs have a cost dimension, and time characterizes the duration of the production or commercial cycles. Inventory optimization involves the values of inventory levels (volume), their structure and movements (updates) of inventory.
As you move along the supply chain, the qualitative and quantitative composition of the flow changes. Initially, between the source of raw materials and the first processing plant, as well as between different industries, as a rule, mass homogeneous goods move. In the woodworking industry, this is a sawlog - logs various breeds wood. As we move forward, the material flow is increasingly transformed into various types of raw materials and products. Lumber is made from sawlogs, for example, for log cabins. The characteristics of the material flow become more diverse. At the end of the chain, the material flow is represented by various, customized, ready-to-consume goods. Within individual industries, material flows also take place. Here, various parts, blanks, semi-finished products are moved between workshops or inside workshops. And each of this subspecies of material flows has its own characteristics - time and cost.
Thus, in the course of the logistics process, the material flow begins with raw materials, and then is brought to the enterprise, where it is “magically transformed” into products as it passes through the chain of technological sections. At the end of the production process, the finished products are delivered to the consumer using vehicles and warehouse operations.
To characterize the intensity of material flows, an indicator of the dimension of the material flow is used, which is a fraction, the numerator of which indicates the unit of measurement of the cargo (pieces, tons, etc.), and the denominator is the unit of measurement of time (day, month, year, etc.). etc.): R = n:t.
The higher the indicator, the higher the intensity of the flow, which indicates a good organization of logistics.
In general, the logistics optimization of the material flow is a complex of economic and mathematical problems, as a result of which an integrated system can be created that provides an economic gain due to a qualitative change in the management of the material flow.

Flows in logistics systems

2.1. The concept of material flow

A person can look endlessly at a burning fire, flowing water and a working person. All of the above apply to streams. The flow is the amount of matter, information, money moving per unit of time.

Fundamental in logistics systems is the material flow generated as a result of transportation, storage, picking and other logistics operations on the way from the primary source of raw materials to the end consumer, including reverse and return flows.

At certain points in time, the material flow can be a stock of raw materials, semi-finished products, work in progress or finished products, if the material flow is at rest.

For ease of management, the flow is considered as a fraction, in the numerator of which is the unit of measurement of cargo (pieces, tons, etc.), and in the denominator - the unit of time (day, month, year, etc.) - t / year; m 3 per month, etc.

The fundamental difference between the logistics approach to material flow management and the traditional approach is as follows. The management of single flows in an enterprise or between enterprises in traditional management is carried out separately. The specificity of the logistics approach lies in the management of a single material flow at the level of an enterprise or a group of enterprises by a logistics service.

In the classification of material flows, the following main groups are distinguished.

Group 1. In relation to the logistics system, the material flow can be: internal and external, incoming and outgoing (Fig. 3).

Group 2. According to the assortment, material flows are divided into single-type and multi-type. Such a separation is necessary, since the assortment composition of the flow significantly affects the work with it. For example, the logistics process in a wholesale food market that sells a mixed assortment will be significantly different from the process in a potato store that works with one item of cargo.

Rice. 3. Material and information flows in relation to the enterprise

Group 3. Depending on the mode of transport, material flows are distinguished by rail, road, water, air and other modes of transport.

Group 4. According to the overall, weight and physico-chemical characteristics of the goods that make up the flows:

– heavy loads (do not provide full use cargo capacity of the vehicle, the mass of one package is more than 500 kg);

- large mass (weight of one package from 100 to 500 kg);

- light weight cargoes (do not provide full use of the carrying capacity of the vehicle, the mass of one package is less than 100 kg);

- oversized cargo (height of one package is more than 3.8 m, width - more than 2.5 m, length - more than the length of the cargo area);

– bulk cargo (carried in bulk); bulk cargo (transported in tanks, bottles and other special containers);

- piece cargo (the unit of measurement of which is pieces); packaged goods (measured by the number of containers - bags, boxes, rolls).

Group 5. According to the method of packaging during transportation, flows are distinguished: in containers; on pallets (pallets); in tanks.

Group 6. According to the nature of the movement of goods in space and time, there are:

- continuous material flows that are formed during the movement of goods using pipeline transport;

are discrete material flows.

Most of the material flows in the spheres of production and commodity circulation are discrete in space and time.

Group 7. According to the degree of determinism of flow parameters:

– deterministic material flows – with fully known parameters;

are stochastic material flows. If at least one of the flow parameters is unknown or is a random variable.

- Group 8. According to the quantitative basis, material flows are divided into:

- mass flows arising in the process of transportation of goods by a group of vehicles, for example, a train;

- large flows - several vehicles, for example, a convoy;

- average flows form goods arriving single, fully loaded vehicles;

- small flows - are formed by the amount of cargo that does not allow full use of the carrying capacity or cargo capacity of the vehicle.

Group 9. By belonging to the functional area of logistics (in the field of supply, production or marketing of goods, etc.).

The study of the constituent parts of the material flow and the features of its movement at the enterprise level or between enterprises allows us to detect "bottlenecks" and is the first step in optimizing the physical movement of goods. At the same time, material, information, financial and service flows should be considered as a whole.

author Shevchuk Denis Alexandrovich

Topic 10. Cash flows of enterprises

author

Topic 8 Transport support in logistics systems 8.1. Essence of transport logistics