• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2015.05a
• /
• pp.123-124
• /
• 2015

The project participants make use of floats for their benefits. The owner may consume floats in an event of issuing change order(s) and may avoid the risk factors attributed by them; the contractor may reduce activities' costs by substituting the activity with alternative construction method and by leveling the resources, hence consuming floats. There are a lot of disputes and claims involved in the float ownership issue. The ownership of floats should be stipulated in the contract stage. To alleviate these disputes and claims, it is commendable to develop a computational method that quantifies the float value. This paper presents the method that computes the values of total floats which changes over the project life span. The system calculates CPM, compute the ratio of area of banana curve which is enclosed by earliest start curve and latest start-curve.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2013.11a
• /
• pp.54-56
• /
• 2013

가상머신을 사용자에게 좀 더 빨리 서비스하기 위해서 서비스 제공자들은 여유 가상머신이나 여유 이미지를 두는 방식을 취해왔으나 이는 근본적인 해결책이 되지는 못했다. 본 논문에서는 가상머신 이미지를 복사하는 시간을 LVM을 이용하여 최소화함으로써 가상머신이 필요한 순간에 필요한 이미지를 이용하여 실시간으로 생성될 수 있도록 설계하였다. 특히 가상머신 이미지의 크기에 무관한 시간이 소요되며 다수의 이미지를 동시에 생성할 시에도 좋은 성능을 보였다.

• Journal of the Korean Society for Railway
• /
• v.15 no.6
• /
• pp.638-644
• /
• 2012

In this study, we numerically estimated available and unavailable time of conventional railway by examining 60% which is known as average range of track utilization efficiency. We also estimated track repair time for maintenance which is the main factor of making track utilization change and analyzed appropriate estimated time. The railway's safety should be guaranteed by appropriate railway operating plan and by adequate rail facilities maintenance. At the same time, daily railway train 'Dia's recovery power should be reflected to the management plan. Considering these factors, we examined mechanical equipment and the national rail network in order to rationally estimate track repair time of the maintenance and to secure spare time in case of train delays. It was found that track utilization efficiency was more or less 60%.

• Journal of Intelligence and Information Systems
• /
• v.15 no.3
• /
• pp.137-150
• /
• 2009

This paper proposes the hybrid heuristic method to apply the opportunity time to solve the vehicle routing and scheduling problem with time constraints(VRSPTW). The opportunity time indicates the idle time which remains after the vehicle performs the unloading service required by each customer's node. In this proposed heuristic, we add the constraints to VRSPTW model for the opportunity time. We also obtain the initial solution by applying the cost evaluation function to the insertion strategy considering the opportunity time. In addition, we improve the former result by applying the opportunity time to the tabu search strategy by swapping the customer's node. Finally, we suggest the construction strategies of initial routing which can efficiently acquire the nearest optimal solution from various types of data in terms of geographical condition, scheduling horizon and vehicle capacity. Our experiment show that our heuristic can get the nearest optimal solution more efficiently than the Solomon's I1 heuristic.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 2007.11a
• /
• pp.68-74
• /
• 2007

Critical Chain Project Management(CCPM) is a new project management system paradigm which maintains the advantages of PERT/CPM and improves the shortcomings of it. In CCPM the task durations are determined as 50% time estimates, ie average time discarding the their contingency. CCPM determines the critical chain the constraint of a projects considering the logical precedence relationship and resource conflict resolution. Project buffer is located at the end of critical chain to absorb the variations of critical chain. The size of project buffer is usually calculated as the half of the sum of critical chain length. Also feeding buffer is inserted after each non-critical chain which feeding into the critical chain to prevent the time delay of critical chain from uncertainties of non-critical chains. Resource buffer can be utilized to improve the availability of resources of critical chain. Buffer management is a project execution and control mechanism. Buffers are classified into 3 zones. They are OK zone, Watch and Plan zone and Expediting zone. If the project status is within Watch and Plan zone, contingency plan is established. And if it changes into Expediting zone, the preplanned contingency plan are executed to recover the time delay. In CCPM the workers are asked to work with relay runner work mechanism that they work fast if possible and report their completion to project manager for the succeeding task to start as soon as possible. The task durations are not considered as the promised time schedule. The multi-tasking is prohibited.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2020.01a
• /
• pp.71-72
• /
• 2020

본 논문에서는 시간과 공간의 제약없이 작물의 생육환경을 관측하고 자동 및 원격으로 제어할 수 있는 스마트팜 플랫폼을 설계 및 구현하였다. 스마트팜 플랫폼은 환경 데이터 수집을 위한 다양한 아두이노 센서 모듈, 웹과 데이터베이스 서버, 애플리케이션을 이용한 자동 및 원격 제어, 총 3가지 기술로 구성된다. 사용자가 앱을 통하여 언제 어디에서나 농장 주변의 환경 정보를 조회하고 원격으로 제어하면 농사에 대한 노동력 절감 뿐만 아니라 시간적·공간적 구속으로부터 자유로워져 여유시간도 늘고 삶의 질도 개선될 수 있을 것으로 기대된다.

• Fire Science and Engineering
• /
• v.24 no.6
• /
• pp.45-53
• /
• 2010

The purpose of this study is to find out the most effective evacuation alarm sound which is the one of the most important element of the evacuation guidance system as a fundamental mechanism to minimize the damages of a fire. In this regard, a survey was conducted against the firefighting officers and the general public with questions about the general awareness of fire and their preference to various kinds of fire alarm sounds. The result showed that 1) even though the awareness of the interviewees on fire was improving while there were in familiar places like homes or works. But, when they were situated in unfamiliar locations, the fire safety awareness could not be deemed to be strong. This in turn calls for the education of the public and improvement of the existing policies for the enhancement of the fire related safety awareness in unfamiliar environments. 2) For the question about the possible time they could survive in a fire or the time required for safe evacuation, it turned out that the interviewees were thinking of the time required for evacuation to be short, which calls for proper actions. 3) When the visibility in a fire situation is highly limited, the most preferred answer for the alarm sound was a female voice, saying "The emergency exit is this way," accompanies with flashing lights of sirens for the emergency evacuation guidance.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.7 no.2
• /
• pp.26-36
• /
• 2008

Currently, the pedestrian signal timing model has no consideration on the characteristics of different land use patterns and pedestrian behaviors during pedestrian signal timing calculation. This study intended to propose pedestrian signal timing models that could reflect the inherent characteristics of pedestrian and land use patterns. For this study, three major variables affecting the length of signal timing were identified: walking speed, perception-reaction time, and density-delay time. Then, the representative values of each variable were estimated through the field studies. By combining this information, several pedestrian signal timing models were developed. The data in this paper can be used for future references, and the walking environments for pedestrians could be improved by applying the models suggested in this paper.

• The KIPS Transactions:PartD
• /
• v.10D no.2
• /
• pp.187-194
• /
• 2003

Main Memory storage system can increase the performance of the system by assigning enough slack time to real-time transactions. Due to its high response time of main memory devices, main memory resident data management systems have been used for location management of personal mobile clients to cope with urgent location related operations. In this paper we have developed a multi-threaded main memory storage system as a core component of real-time retrieval system to handle a huge amount of readers and writers of main memory resident data. The storage system is implemented as an embedded component which is working with the help of a disk resident database system. It uses multi-threaded executions and utilizes latches for its concurrency control rather than complex locking method. It only saves most recent data on main memory and data synchronization is done only when disk resident database asks for update transactions. The system controls the number of read threads and update threads to guarantee the minimum requirements of real-time retrievals.

• Journal of the Korea Society of Computer and Information
• /
• v.19 no.3
• /
• pp.155-161
• /
• 2014

The objective of this study is to weight analysis portable backpack system of infantry weapon systems for ergonomic design in manual materials handling tasks. For the product design, we analyzed the ergonomic guidelines and status of similar weapon systems by comparing the efficient operation performance provide for the basic data. Result of this study, the relationship between portability and mobility presented for schematic. In the short distance of the short biomechanical criterion, 1-2 hours in the middle of moving psychophysical criterion, 4 hour or more long-distance criterion applied for the physiological criterion for easy of trade-offs that need to be considered. This study suggests for 4 research items for infantry backpack system in manual materials handling tasks. Throughout the result of anthropometric populations, the 5%tile body weight for -0.91kg but 95%tile in 34.17kg considered to be margin for free, easy and efficient operation for the weight margin between portability and mobility in manual materials handling tasks.