Project Scheduling
”
D.B.Hanchate1, S.A.Shinde2, Y.N.Sakhare3, S.S. Kare4
1Asstistant Professor in Computer Engineering (PG), VPCOE, Baramati, Pune, Maharashtra (India).
2
Assistant Professor in Information Technology , VPCOE, Baramati, Pune, Maharashtra (India). 3
M.E. Computer (II) year student at VPCOE, Baramati, Pune, Maharashtra (India) 4
M.E. Computer (II) year student at SCOE, Pune, Maharashtra (India) ([email protected]), ([email protected]), ([email protected]) ,([email protected])
Abstract–In project management ,mainly scheduling refers to a set of policies and mechanisms to control the order of work performed .In scheduling of project there are many problems such as general employee scheduling problem, Bus driver scheduling problem, Scheduling problem in self suspending tasks. Resource scheduling problem ,university class scheduling problem and so on.
Conflict measurement is one of the key tasks for project scheduling. This work is mainly focusing on parameters that affects to conflicts in project scheduling &identification of conflicts .This work gives the related work that create conflict free schedule while maintaining the resource constraints done by various authors.
Keywords – Scheduling, Scheduling problem(SP),Optimization, Genetic algorithm(GA),Win Win model.
I. INTRODUCTION
Our work is dealing with the very special domains
fromsoftware project management viz.„scheduling „. Software Project Scheduling is generally contained in the software development project plan. Most of the commercial companies use scheduling methods to arrange the task systematically to improve product quality and customer service quality by reducing different overlaps i.e. conflicts in the schedule [2].
In the scheduling methods, there are various types of constraints such as resource constraints, time constraints etc. Sometimes due to these varied types of constraints, conflict does occur in project scheduling. This paper presents a survey of different scheduling problems, parameters that leads to conflicts in project scheduling, identification techniques to identify conflicts in project scheduling. It also puts a light on the remedies for creating and analyzing the conflict-free schedule.
If a user submits a schedule containing various parameters like Human resource, start time, end time, duration task leader ,location etc. due to overlapping of such parameters causes problems in scheduling and sometimes these problems causes conflicts. so, first we need to search problems in scheduling because of these parameters and then identification of such conflicts in any project scheduling After identification ,these conflicts can be resolved with some resolution techniques[16] .
II.PROJECT SCHEDULING
Project Scheduling is the process of identifying and organizing the tasks of a project into a sequence of events ensuring a harmonious completion of the venture. These events are dependent on the results of their preceding
activities, thus interlinking all the activities of the project. In project scheduling a time line is set for all the activities in the project. This involves examining the interdependencies of all of the activities, and coordinating all the tasks to ensure a smooth transition from the beginning to the end of the project. This interdependency provides for a major need of effective project scheduling. There are many different types of scheduling.
III. TYPES OF PROJECT SCHEDULING
Short term, mid term and long term scheduling:-These systems defined by the Franco callri[16] uses short term, mid term and long term on the basis of how much time is required to complete the given activity.forward scheduling and backward scheduling methods used to find finish time of work if start time is known and find start time if finish time is known for the task by estimating the efforts required completing that task respectively[20].
A.Critical Path Method:The Critical path method is a pictorial representation of the project that is useful for identifying the overall length of time that a project will take. It also demonstrates which activities are necessary to complete the project and those that are not as critical. In this technique, the project is represented pictorially as a network, where the nodes represent activities and the duration of an activity is represented by lines or arcs in between nodes. The duration of each activity is estimated based on industry knowledge. Before constructing a diagram, the activities need to be identified, as does the sequencing these events[19].
E g, Activities A and B might occur simultaneously prior to activity C, producing a diagram with the following overall shape: " >," where the upper left end would have node labeled A, the lower a node labeled B, and the point at the right side would have a node labeled C.
A
C
B
path method the activities and their duration are defined.
C .Gantt Charts:Gantt charts are a pictorial representation of the phases and activities of a project, and they are typically applied to plans in a setting in which there is little variation among the projects. These charts graphically illustrate the start and end dates of a task with horizontal bars under a horizontal line representing the date. Information about the complexity or size of task is not accounted for, so a bar representing a relatively small task can have the same pictorial representation as a larger one if the timing is similar. This can causea problem if an activity is behind schedule.
IV.
CONFLICTS
IN
PROJECT
SCHEDULING:-Conflict is an expressed struggle between at least two interdependent parties who persive incompatible goals ,share the resources and interference from other in achieving their goals. Conflict may originate from a no. of different sources including differences in information ,Beliefs ,values, interests. Conflict reduces similar thinking in a group.There are different types of conflict such as workplace conflict, Inter group conflict, inter-individual conflict and intra-individual conflict.
V.
SCHEDULING
PARAMETERS:-
There are different scheduling problems present in project scheduling such as Bus driver scheduling problem, employee scheduling problem, etc having set of parameters. According to Helena Ramalhinho Lourenço,bus driver scheduling problem finding the minimum cost and set of feasible daily duties that cover all the trips to meet heuristic approach[5]. General employee scheduling problem arises in variety of service delivery settings,including scheduling of nurses in hospital ,check encoders in bank, hotel, hospital ,petrol offices etc[17].Full-Time and Part time Employee’s:-Fred Gloyer and Claude says , as the shift scheduling problem, is assumed in the general employee scheduling problem that some fraction of the work will be done by full-time employees and the remainder by part-time employees. Full-time employees are those entitled to work a number of hours each week (commonly 40) and generally work shifts of standard duration (commonly 8 hours each)[17].In general employee scheduling, the number of employees on duty, all shifts assignment ,hours (duration)[4] employees assigned to shift are some of the parameters defined. Some scheduling parameters creates conflicts in project scheduling. Scheduling parameters and their effects are list out . In course scheduling, No of Instructors ,Classrooms ,Lecture time and Course name are the parameters [6].
In this problem ,Conflicts can occur due to one HR on multiple course , one HR on multiple classes at the same time and so on ,Job scheduling having some parameters such as load balance, throughput, priority, availability, Resource utilization
resource scheduling is having Capacity bounded ,no of agents and resource held duration parameters[8]. In Medical Office scheduling appointments, time, HR, place are some parameters identified[13].
VI. IDENTIFICATION TECHNIQUES
:-To create conflict free schedule , it is necessary to identify the conflicts in scheduling. Some of the techniques are list out: 1.Integer linear programming is used For University class scheduling problem[Ahmed Wasfy and Fadi A. Aloul][6]. 2.A. Elkyari, C.Guret, and N. Jussien says that an explanation based constraint programming technique for dynamic project scheduling problem to handle dynamic RCPSP instances. This technique provide optimal solution to be able to handle large number of different unexpected events and computes a new solution quicker than solving the new problem from scratch. The successive computed solutions are much more stable than solutions computed from scratch. An explanation is set of constraints that justifies the action of solvers .In this an optimal solution for the original problem is computed .Unexpected events are handled incrementally from this first solution, upon addition of new information if conflicts identified with current solution re-optimization is performed .Conflict is analyzed using recorded explanations .Some past decisions are undone some new decisions are made until new optimal solution is obtained[7] .
3.Drum Buffer Rope scheduling [3].
According to Zhaofu Tian & Shingling Zhang, Wuliang Peng, Critical chain project management[CCPM] for scheduling of multi-project management[1].
Scheduling of multi-project management can be used for resource conflict problem which exists the challenges ,co-ordination ,Lack of dynamic and Scheduling plan[1]. Critical chain project management applied the Theory of constraints (TOC) management principle to the project management planning with limited resources for eliminating bad conduct of the work and ensuring that the entire project execution by manage the buffers to the management. The process of scheduling implement with critical chain which is having different buffers[1].Project buffer-To protect project duration with overall project buffer Feeding buffer-At the entrance of non critical chain to critical chain to protect the critical chain.
Resource buffer –To alternate each project to scheduling resources among different projects.
Buffer Management Mechanism [Zhaofu Tian & Shingling Zhang, Wuliang Peng]
Critical chain Project management uses buffer mechanism: 1) To monitor the overall mission of the project.
There are three sections of task chain[1] :
1)If task chain is lower than 1/3 Of the total buffer then it implements well(green zone)
2)If Consumption of buffer is 1/3 to 2/3 then task is in trouble(yellow zone) and
3)If buffer consumption of the task is more than 2/3 of total buffer then there is Serious problem in progress
It indicates with Red zone.
Zhaufu & his team has suggested the priority scheduling by making the formula as
differential ratio of time of [project[i]] = (difference(Latest_start_time[project[i]],Current_time[project[i ])/difference( actual_start_time[project[i]), earlier_star_time(project[i]) )
priority(project[i]) = differential ratio of time of [project[i]]*Cost( project[i])/Total_cost_all_project
where project i=1to n,+1
Because of limited resources , resource conflicts can occur among the projects. Therefore, it should identify the task of resource conflicts among projects by using relational algorithm. Relational algorithm is defined by Zhao Tian and Wuliang Peng ,gives the difference between starting and end time .If the difference between the start time and end time of a particular task is zero then resource conflict between that task otherwise that tasks can be done at the same time[1].
Task Resource Conflicts by identifying conflicts and Alternating project to avoid Resource Conflicts:- After identifying resource conflicts among projects, it needs to alternate each project by using certain rules in
order to achieve the resource scheduling among different projects.
Resources Buffer Mechanism.:- The project managers arrange the project group according to project priority and urgency of the project. Then it should alternate the task Shares the same resource[1]
Multi-project management is divided into the following steps:
Calculate priority of each project
Plan and schedule each schedule in accordance with CCPM
Identify the task of resource
Set the project and feeding buffer.
Manage the buffer Zone effectively.
END
according to priority of the task of resource conflict among different projects and add capacity buffer (CB) into resource conflicts between the projects to balance resources sharing. The size of the CB and buffer management techniques is conducted in accordance with CCPM.
V. CONFLICT RESOLUTION
TECHNIQUES:-As M.Ramzan,M.Qasim Khan,
M. Amjad Iqbal says the major problem in these software project management is that, it often faces conflicts with each other .Conflicts resolution is not a simple job . Different strategies where used for this purpose. Conflict resolution is still an optimization problem because from time to time rate of conflicts is reduced. Therefore there is need to use some optimization techniques that reduces number. of iterations[15].Optimal project scheduling is the critical activity in project scheduling there is the processing of evaluating the performance of techniques in various scheduling data sets. In multi projectmanagement, in calculating time
Comparative study of different Conflict identification and resolution
techniques[15]:-ResolutionTechniques
Input Parameters Process/model Performance/Need Output/Result
Theory X (Papa at. al)2008 Employees, schedule, tasks. Managers, time, tasks, employees. Management oriented process
End with blame, So negative view about theory, hard to find solution
Conflict resolution with management .
Theory Y (Papa at. al)
Employees ,schedule, tasks. Training Methodologies, Employees capacity ,time. Responsibility assigned to Employees. Work for
Employee is as natural as to do.
They have
capacity to solve the problem. Conflict resolution is upto employees own consideration. Theory Z-Japan style management Employees ,schedule ,goals
Goals ,loyalty. Goal set before working and they are eager to perform goals. Provides strong mechanism for achieving the project goals Conflict resolut by with sett project goals. Theory W (Barry et.al) 1996 Stakeholders ,Managers,
Human Resource, Performs through mutual consideration ,Everyone is considered to win.
Everyone is winner due to its nature,
One party has to lose their views after negotiation PM identifies the problems while resolving different people of different fields. Pairwise comparison method(PCM) (Hameed,2008 ) List of requirements, Human resource Requirments ,priority ,weights prepare contribution Matrix and assign
values to
requirements .If requirments co-inside with another then requirements replaced by weights.
Requirements relates to positive and negative impact.It gives high priority on the basis of greater weights.
Solve conflicts among
stakeholders giving priority to the conflicts
Win-Win model (Ln et.al) 2005
Schedule, human resource.
Agreements, HR requirements.
Use theory W, Use spiral model for resolving conflicts
Brought comman interest where Party is satisfied . They did Not lose everything.Negoti ation Resolution of conflicts in requirements within stakeholders, Genetic algorithm (Darwins theory) Project Schedule activities Activity name,Hr,Earlist start time(EST),Earlie st finish time(EFT),locatio n,duration,Rule set.
Process of guessing ,activity Evaluation against Rule set.
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