• Journal of the Korea Institute of Building Construction
• /
• v.10 no.4
• /
• pp.31-39
• /
• 2010

As the linear scheduling method has been used since the Empire State Building linear schedule in 1929, it is being applied in various fields, such as construction and manufacturing. When addressing concurrent critical paths occurring in a linear construction schedule, empirical researches have stressed resource management, which should be applied for optimizing workflow, ensuring flexible work productivity and continuous resource allocation. However, work relationships have been usually overlooked in making the linear schedule from an existing network schedule. Therefore, this research analyzes the previous researches related to the linear scheduling model, and then proposes a method that can be applied for adopting the relationships of a network schedule to the linear schedule. To this end, this research considers the work relationships occurring in changing a network schedule into a linear schedule, and then confirms the activities movement phenomenon of linear schedule due to workspace change, such as physical floors change. As a result, this research can be used as a basic research in order to develop a system generating a linear schedule from a network schedule.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2010.05a
• /
• pp.131-133
• /
• 2010

As linear scheduling method has been used since 1929, Empire State Building linear schedule, it is being applied in various fields such as construction and manufacturing. When addressing concurrent critical path occurring on linear schedule of construction, the empirical researches stress the resource management which should be applied for optimizing work flow, flexible work productivity and continuos resource allocation. However, work relationships has been usually overlooked for making the linear schedule from existing network schedule. Therefore, this research analyze the previous researches related to linear scheduling model and then propose the method that can be applied for adopting the relationships of network schedule to the linear schedule.

• Journal of Korean Institute of Industrial Engineers
• /
• v.27 no.2
• /
• pp.140-149
• /
• 2001

The paper discusses the problem of finding the Origin-Destination(O-D) shortest paths in internodal transportation networks with time-schedule constraints. The shortest path problem on the internodal transportation network is concerned with finding a path with minimum distance, time, or cost from an origin to a destination using all possible transportation modalities. The time-schedule constraint requires that the departure time to travel from a transfer station to another node takes place only at one of pre-specified departure times. The scheduled departure times at the transfer station are the times when the passengers are allowed to leave the station to another node using the relative transportation modality. Therefore, the total time of a path in an internodal transportation network subject to time-schedule constraints includes traveling time and transfer waiting time. In this paper, a genetic algorithm (GA) approach is developed to deal with this problem. The effectiveness of the GA approach is evaluated using several test problems.

• ETRI Journal
• /
• v.39 no.3
• /
• pp.364-372
• /
• 2017

For the reliability of controllers in a software defined network (SDN), a dynamic and self-learning schedule method (DSL) is proposed. This method is original and easy to deploy, and optimizes the combination of multiple controllers. First, we summarize multiple controllers' combinations and schedule problems in an SDN and analyze its reliability. Then, we introduce the architecture of the schedule method and evaluate multi-controller reliability, the DSL method, and its optimized solution. By continually and statistically learning the information about controller reliability, this method treats it as a metric to schedule controllers. Finally, we compare and test the method using a given testing scenario based on an SDN network simulator. The experiment results show that the DSL method can significantly improve the total reliability of an SDN compared with a random schedule, and the proposed optimization algorithm has higher efficiency than an exhaustive search.

• Journal of the Korea Institute of Building Construction
• /
• v.11 no.1
• /
• pp.1-8
• /
• 2011

Linear scheduling method limits to present works of work breakdown structure as a form of lines and was often developed manually. In other words, linear schedule could not utilize activity, work breakdown structure, and etc. information of network schedule such as CPM(Critical Path Method) and has been used only for reporting or confirming construction master plan. Therefore, it is necessary to develop system which can automatically generating the linear schedule based on the network schedule having many accumulated and useful construction schedule information. Thus, this research has an effort to establish data process model, data flow diagram, and data model in order to make linear schedule. In addition, this research addresses the system solution structure, user interface class diagram and logic diagram, and data type schema. The results of this paper can be used as a preliminary research for developing linear schedule generating system prototype by utilizing the network schedule information.

• Journal of Communications and Networks
• /
• v.18 no.2
• /
• pp.227-237
• /
• 2016

Data collection is a key function for wireless sensor networks. There has been numerous data collection scheduling algorithms, but they fail to consider the deep and complex relationship among network lifetime, sink aggregated information and sample cycle for wireless sensor networks. This paper gives the upper bound on the sample period under the given network topology. An optimal schedule algorithm focusing on aggregated information named OSFAI is proposed. In the schedule algorithm, the nodes in hotspots would hold on transmission and accumulate their data before sending them to sink at once. This could realize the dual goals of improving the network lifetime and increasing the amount of information aggregated to sink. We formulate the optimization problem as to achieve trade-off among sample cycle, sink aggregated information and network lifetime by controlling the sample cycle. The results of simulation on the random generated wireless sensor networks show that when choosing the optimized sample cycle, the sink aggregated information quantity can be increased by 30.5%, and the network lifetime can be increased by 27.78%.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.21 no.6
• /
• pp.712-717
• /
• 2011

Recently, diverse schedule management agents are being researched for the efficient schedule management of smart devices users, but they remain at a confirmatory level. In order to efficiently manage user's schedules, execution of planned schedules should be monitored to help users properly execute their schedules, or feedback must be given so that when setting up new schedules, users can plan their schedule according to their schedule establishment patterns. This research proposes a schedule management agent that infers the user's behaviors by using acquired user context, and provides schedule related feedback depending on the user's behavior patterns, when users are executing their schedules or planning new schedules. For this, collected user context information is preprocessed and user's behavior is inferred by Bayesian network. Also, in order to provide feedbacks necessary for confirming the user's schedule execution and new schedule establishment, a context tree pattern matching method for the user's schedule, location and time contexts was applied, then verified with 6 weeks of user simulation in a mobile environment.

• Journal of the Korea Institute of Building Construction
• /
• v.12 no.6
• /
• pp.558-565
• /
• 2012

Schedule management of construction work is critical to completing construction projects within a given period of time. Many efforts have been made and multiple tools have been developed to support the management of construction projects using smart devices such as smartphones and tablet PCs. This study proposed a method for managing construction schedules via a smart device using Flash. The interactive and graphic properties of Flash enable the development of an app that can allow a field manager to manage schedules easily and efficiently. A prototype was implemented using Adobe Flex Builder, and a sample network was applied in a smartphone. It is convenient for a construction manager to manage construction schedules using the tool because Flash controls graphic components easily. In further studies, network diagrams such as CPM (Critical Path Method) should be developed and applied to the app.

• Architectural research
• /
• v.11 no.2
• /
• pp.43-49
• /
• 2009

Since the late 1980s, the schedule technique applied to the construction industry around the world has rapidly changed from the traditional ADM (Arrow Diagramming Method) to the PDM (Precedence Diagramming Method) technique. The main reason for this change is to overcome the limits and inconveniences of the traditional ADM technique. The time-cost trade-off is one of the core scheduling techniques to establish the best optimized combination plan in terms of a relationship between the cost and schedule. However, most of the schedule-related textbooks and research papers have discussed and proposed applications of a time-cost trade-off technique based only on the Finish to Start relationship. Therefore, there are almost no consideration and discussion of problems or restrictions that emerge when the time-cost trade-off technique is applied to the PDM network that has overlapping relationships. This paper proposes the lead-time adjustment method as a methodology for overcoming some restrictions that are encountered when the time-cost trade-off technique is applied to the overlapping relationships of the PDM network.

• Journal of Astronomy and Space Sciences
• /
• v.31 no.1
• /
• pp.51-61
• /
• 2014

In this work, the preliminary analysis on both the tracking schedule and measurements characteristics for the spacecraft on the phase of lunar transfer and capture is performed. To analyze both the tracking schedule and measurements characteristics, lunar transfer and capture phases' optimized trajectories are directly adapted from former research, and eleven ground tracking facilities (three Deep Space Network sties, seven Near Earth Network sites, one Daejeon site) are assumed to support the mission. Under these conceptual mission scenarios, detailed tracking schedules and expected measurement characteristics during critical maneuvers (Trans Lunar Injection, Lunar Orbit Insertion and Apoapsis Adjustment Maneuver), especially for the Deajeon station, are successfully analyzed. The orders of predicted measurements' variances during lunar capture phase according to critical maneuvers are found to be within the order of mm/s for the range and micro-deg/s for the angular measurements rates which are in good agreement with the recommended values of typical measurement modeling accuracies for Deep Space Networks. Although preliminary navigation accuracy guidelines are provided through this work, it is expected to give more practical insights into preparing the Korea's future lunar mission, especially for developing flight dynamics subsystem.