Wyniki wyszukiwania - Biblioteka Nauki

1

An investigation into the influence of activity duration time fuzziness on critical path parameters

100%

Piech H. , Machura M.

Prace Naukowe Instytutu Matematyki i Informatyki Politechniki Częstochowskiej

|

2004

|

tom Vol. 3, nr 1

165--173

EN

Resources and fuzziness influence in a crucial way critical path parameters such as length and configuration. An algorithm establishing the order and range of the analysis by changing the activity duration time values, resulting from the fuzziness range in each node, will be formulated to investigate this influence. The research strategy selection has an essential influence upon the results, their range and quality and their reliability. The obtained results, applying the canons of engineering backwards, can be used to regulate the fuzziness range thereby controlling the course and length of the critical path.

2

Organization of work of transportation means in combined transport

70%

Marczuk A. , Misztal W.

Journal of KONES

|

2013

|

tom Vol. 20, No. 3

267--274

EN

The paper deals with an analysis of selected scheduling methods in a view of their use in planning the work of transportation means. The implementation plans for specific transport processes, for which duration of the project procedure is aimed at creating the optimal is the criterion. The authors will attempt to develop a coherent procedure for the combined transport, i.e. transport processes carried out by means of transportation means in more than one mode of transport. It may be also applied for the use of a number transportation means from the same transport branch, when there is a necessity to perform the handling works. Optimization of the execution time for the transport project, that is a modified version of classical transportation problem and scheduling method were applied for creating the method. The procedure can also be used to capture solutions resulting in an excessive use of transportation means, e.g. in case, when too many sets of transport are used. The method is a very useful tool for creating the scheduling of transportation means work. it lets on to fitting an appropriate response to the existing situation resulting from potential delays. It provides valuable information in terms of dispatchers, other managers handling with loads, as well as those involved in the determination of parameters related to contracts for transport projects

3

A timed Petri net framework to find optimal IRIS schedules

60%

Werner M.

Control and Cybernetics

|

2006

|

tom Vol. 35, no 3

703-719

EN

IRIS (increasing reward with increasing service) realtime scheduling appears frequently in real-time control applications such as heuristic control. IRIS requires not only meeting deadlines, but also finding the schedule with the best result (highest reward). In this paper, a framework is presented that uses Timed Petri nets (TPN) to transform an IRIS problem into a dynamic programming (DP) problem, allowing the application of known TPN and DP techniques. In the presented approach, an IRIS problem with tasks having discrete-time optimal parts is transformed into a (possibly unbounded) TPN. Then, the critical path problem of the TPN state graph can be tackled with DP. This approach allows for the IRIS problem multiple constraints and negative rewards.

4

Efficiency analysis of the Kaufmann and Desbazeille algorithm for the deadline problem

60%

Anholcer M. , Gaspars-Wieloch H.

Operations Research and Decisions

|

2011

|

tom Vol. 21, No. 1

5-18

EN

Time-cost tradeoff analysis is a very important issue in project management. The Kaufmann–Desbazeille algorithm is considered by numerous authors to be an exact algorithm to solve this problem. In the paper, we prove that this claim is not true. In particular, we perform a worst-case analysis. The accuracy of the KDA is the worst when: the network has many critical and subcritical paths with a lot of common arcs (i), shortening costs are constant (ii), the level of shortening costs for a given activity depends on its type.

5

The critical chain method in project management - a formal description

51%

Kuchta D.

Badania Operacyjne i Decyzje

|

2004

|

tom nr 1

37-51

EN

The critical chain methods is a recent alternative to the traditional critical path method, an alternative which is becoming more and more popular, but still lacks a formal description. It exists more or less on the level of ideas and seems to have quite a lot of gaps and non-researched areas. This paper constitutes an attempt to create a formal description of the method, trying and the same time to fill in some of the gaps and to indicate a further need for OR research.

PL

W 1997 roku E Goldratt zaproponował alternatywę dla tradycyjnego podejścia do zarządzania czasem projektu i harmonogramowania - metodę łańcucha krytycznego. Jest to podejście obiecujące, na co wskazują coraz liczniejsze głosy z praktyki. Niestety, brakuje formalnego usystematyzowania metody, analogicznego do formalnego sformułowania problemu ścieżki krytycznej. Metoda łańcucha krytycznego istnieje raczej na poziomie idei, które w mniejszym lub większym stopniu są wcielane w praktyce. Jej opisy w literaturze zawierają sporo luk. W niniejszym artykule zaproponowano zatem formalny zapis metody. Uzupełniono w nim wiele luk istniejących w dotychczasowych opisach metody, podano formalne wzory do wyznaczania podstawowych elementów zarządzania projektem przy zastosowaniu metody łańcucha krytycznego: buforów, ich wielkości, przewidywanej długości realizacji projektu - które pozwalają na stworzenie komputerowej implementacji metody. Jednocześnie wskazano na trudności w formalnym zapisie niektórych aspektów metody - dotyczące zarządzania zasobami. O ile stosunkowo łatwo jest zapisać ideę zarządzania zasobami projektu w metodzie łańcucha krytycznego, o tyle formalny zapis - bez którego pełna komputerowa implementacja metody byłaby niemożliwa - wymaga dalszych badań.

6

Impact of baseline terms on the course of critical paths and time buffers in the modified Goldratt’s method

51%

Połoński M. , Pruszyński K.

Archives of Civil Engineering

|

2013

|

tom Vol. 59, nr 3

313--320

EN

The introduction of a baseline term to the dependency network most often results in a change, break and/or generation of a new sequence of critical path, depending on the type of such a baseline term and the exact date selected. Each of those situations has an impact on the location or need to include new time buffers in the modified Goldratt’s method. The purpose of this article was to identify possible effects brought by declaration of each type of baseline term and to point out actions to be taken in each case. It must be noted that guidelines provided should in each individual case be adapted to the specific character of schedule changes caused by implementation of the relevant baseline term. The example presented herein exemplifi es one of such solutions to be implemented as a result of break of the critical path and need to introduce new time buffers.

7

Accuracy of the Kaufmann and Desbazeille algorithm for time-cost trade-off project problems

41%

Anholcer M. , Gaspars-Wieloch H.

Przegląd Statystyczny

|

2013

|

tom 60

|

nr 3

341-357

EN

The time-cost tradeoff analysis is a very important issue in the project management. The Kaufmann-Desbazeille method is considered by numerous authors as an exact algorithm to solve that problem, but in some articles it has been proved that for specific network cases the procedure only leads to quasi-optimal solutions. In this paper we calculate the average accuracy of the algorithm for several deterministic and randomly generated networks. The accuracy of the KDA is the worst when: - the network is generated in a deterministic way (an even number of nodes, the network contains only arcs connecting neighbouring nodes, neighbouring even nodes and neighbouring odd nodes, thus it has many critical and subcritical paths with a lot of common arcs), - each type of activities in such a network has very specific time-cost characteristics. The structure of the network has the influence on the performance of KDA. It should be however analyzed together with the distribution of the shortening costs.

PL

Analiza czasowo–kosztowa jest bardzo ważnym elementem zarządzania projektem. Algorytm Kaufmanna–Desbazeille dla tego problemu jest przez wielu autorów określany mianem dokładnego, lecz w kilku pracach wykazano, iż w niektórych przypadkach stosowanie tej procedury prowadzi jedynie do rozwiązań bliskich optimum. W artykule wyznaczamy średnią dokładność algorytmu dla pewnej liczby sieci o z góry ustalonej bądź losowo wygenerowanej strukturze. Dokładność procedury Kaufmanna i Desbazeille jest najniższa, gdy: - sieć jest generowana w sposób deterministyczny (parzysta liczba węzłów, sieć składa się z samych łuków łączących sąsiednie węzły, sąsiednie węzły parzyste i sąsiednie węzły nieparzyste, a więc posiada wiele ścieżek krytycznych i podkrytycznych ze wspólnymi łukami), - każdy typ czynności w tak skonstruowanej sieci ma bardzo specyficzne charakterystyki czasowo-kosztowe. Struktura sieci ma wpływ na wydajność algorytmu. Powinna być jednak analizowana łącznie z rozkładem jednostkowych kosztów skrócenia czynności.

8

Harmonogramowanie realizacji przedsięwzięć budowlanych z uwzględnieniem buforów czasu wyznaczonych na podstawie analizy ryzyka

41%

Połoński M. P.

Budownictwo i Architektura

|

2013

|

tom Vol. 12, nr 1

47--52

PL

Zaproponowana w artykule metodyka przygotowywania harmonogramów budowlanych wynika z próby połączenia dwóch niezależnych podejść w celu zwiększenia prawdopodobieństwa dotrzymania planowanych terminów w harmonogramach sieciowych w trakcie realizacji robót budowlanych. Analiza ryzyka planowanego przedsięwzięcia budowlanego pozwoli wskazać zadania, które są najbardziej zagrożone przekroczeniem przewidywanych czasów ich trwania. Zastosowanie buforów czasu, ich właściwa lokalizacja w harmonogramie oraz wyznaczenie wielkości czasu ich trwania z uwzględnieniem przewidywanego ryzyka wystąpienia opóźnień, pozwolą skonstruować harmonogram, zawierający uzasadnione rezerwy czasu rekompensujące ewentualne opóźnienia. Tak opracowany harmonogram może stanowić zarówno wiarygodną podstawę wyznaczenia przewidywanego terminu zakończenia prac na budowie, jak również zarządzania tymi robotami w okresie ich realizacji.

EN

The methodology of development of building project schedules, proposed in the article, is based on an attempt to combine two independent approaches in order to increase the probability of fulfillment of time limits planned in the CPM schedules during the performance of construction works. The analysis of the risk associated with the planned building project will allow for the determination of those tasks which are most threatened by the exceeding of the planned duration time. The application of time buffers, their proper location in the schedule and the determination of their duration, taking into account the expected risk of delays, allow to develop the schedules that contain the appropriate time reserves to compensating for the possible delays. Such a schedule may serve not only as a reliable basis for the determination of the expected deadline for completion of construction works, but also for the management of these works during performance. Selected components of MOCRA and MP-KP methods were proposed in the article.

9

Zarządzanie zasobami ludzkimi w projekcie w kontekście teorii ograniczeń

41%

Mańka A.

Zarządzanie Przedsiębiorstwem

|

2017

|

tom Vol. 20, nr 3

25--31

EN

Many of the problems in the projects are due to bad communication. We should keep in mind that working in a team, a distinctive design for your organization, you can briefly be described as TEAM work, which in the context of the phenomenon of synergy, as a consequence, work in a team can be explained as “Together Each one Achieve More”. These management team issues can be seen in a single project. Companies implementing several projects at the same time to meet multiple of these problems. This work shows the question of human resources management in the Organization, and more importantly design multiple concepts andanalyses the issue of human resources in the context of the theory of constraints (TOC).