• Journal of the Korean Wood Science and Technology
• /
• v.12 no.1
• /
• pp.31-37
• /
• 1984

For the modification of kiln drying schedule, relations between resistance to drying Rd and the moisture content or drying times were found for 4/4, 6/4 and 8/4 green Douglas fir heartwood by the mild drying schedule and the severe drying schedule until the average moisture content was about 10 percent. The results of this study were as follows. 1. Resistance to drying of thicker lumber was higher than that of thinner lumber and resistance to drying of three different thicknesses were negligible between the mild-and the severe drying schedule. The relationships between resistance to drying and two schedules or three thicknesses of lumber were $Rd_1=1.830{\times}10^5\;M^{-2.24}$ for 4/4 lumber by the mild drying schedule, $Rd_2=1.822{\times}10^5\;M^{-2.25}$ for 4/4 lumber by the severe drying schedule, $Rd_3=2.352{\times}10^5\;M^{-2.14}$ for 6/4 lumber by the mild drying schedule, $Rd_4=3.457{\times}10^5\;M^{-2.27}$ for 6/4 lumber by the severe drying schedule, $Rd_5=1.317{\times}10^6\;M^{-2.56}$ for 8/4 lumber by the mild drying schedule, $Rd_6=8.267{\times}10^5\;M^{-2.40}$ for 8/4 lumber by the severe drying schedule. 2. Thinner lumber exhibited lower level of moisture content and shorter drying time required at intersection point between the moisture content and resistance to drying as a function of drying time than those of thicker lumber. Drying time of mild drying was longer than that of severe drying and similar to the level of moisture content at intersection point.

• 정보저장시스템학회:학술대회논문집
• /
• 2005.10a
• /
• pp.139-144
• /
• 2005

Because of the photorefractive recording dynamics, each newly recorded hologram partially erases all previously stored image. Thus achieving the desired diffraction efficiency profile for the entire sequence after all images have been recorded requires exposure time schedule. The often cited classical exposure-schedule model predicts a rising-exponential build-up and an exponential decay in An with an exposure time. However because we cannot directly measure the An, it's difficult to establish the relation of both. In this paper, we deduce the relation of diffraction efficiency and exposure time from experiment data and suggest an algorithm to make time schedule profile in angle/fractal multiplexing of holographic data storage. After that, we present simulated result with equal hologram diffraction efficiency for a sequence of 250 holograms recorded by angle/fractal multiplexing.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2018.11a
• /
• pp.114-116
• /
• 2018

본 논문에서는 빔-호핑 위성 전송 시스템을 위한 카운터를 기반의 연속적인 beam allocation time schedule (BATS) 변경 기법을 제안한다. 제안하는 기법은 BATS 를 처음 변경할 때, 카운터를 기반으로 gateway (GW)와 space craft (SC) 양단에서 BATS 변경 시점을 동기화 시킨다. 이 후, BATS를 계속 변경하더라도 전송 데이터 손실 없이 BATS 를 변경할 수 있다.

• Information Systems Review
• /
• v.6 no.2
• /
• pp.195-208
• /
• 2004

In this paper we propose a new software project development management model incorporating quality management to schedule management. Though many efficient techniques such as code review and inspection are used to remove defects, the effect of defect removal time on project schedule hasn't been studied much. However, poor quality management has an important effect upon overall schedule and sometimes software projects fails due to it. Thus, quality management and schedule management should be considered together and we need to reflect the time to maintain software quality into the schedule management. For the proposed model we introduced "Quality Value" representing the needed time to remove software defects. We assume PSP/TSP to gather the needed data for quality value. The proposed model can be used to predict the effect of software defects on schedule in advance and to prevent schedule lag.

• Journal of the Korean Wood Science and Technology
• /
• v.18 no.1
• /
• pp.39-51
• /
• 1990

This research was carried out to offer the basis data for development of optimum drying schedule for a domestic oak species (Quercus grosseserrata B1.) by investigating drying rate. stress, defect, and moisuture gradient with board thicknesses and drying schedules (code number T4-C2 and T3-B1). The results were obtained as follows: 1. Average drying rate and total drying time from 52.2% to 5.8% were 0.105%/hr and 486 hours for drying schedule T4-C2 and those from 62.1% to 8.3% were 0.070%/hr. and 811 hours for drying schedule T3-B1. 2. Drying rates for 28mm- and 31mm-thick boards showed similar tendency, but were significantly different from 25mm- thick board in drying schedule T4-C2 and those for 22mm-, 25mm- 28mm- and 31mm-thick boards showed similar tendency but were significantly different from 19mm- thick boards in drying schedule T3-B1. 3. The moisture gradients for drying schedule T4-C2 were steeper than those for drying schedule T3-B1 during drying period. and especially in early drying stage slow slope of moisture gradients of drying schedule T3-B1 was effective in preventing serious problem of surface checks. 4. Drying stresses were lower in drying schedule T3-B1 than in drying schedule T4-C2 during drying period. 5. Drying schedule T4-C2 was appropriate for 25mm-thick board but not for 28mm- and 31mm-thick board because of strong drying condition. Drying schedule T3-B1 was appropriate for 28mm- and 31 mm-thick board but not for 19mm-, 22mm-, and 25mm-thick board because of weak drying condition.

• Journal of Information Processing Systems
• /
• v.7 no.4
• /
• pp.613-626
• /
• 2011

In this paper, we focus on the pinwheel task model with a variable voltage processor with d discrete voltage/speed levels. We propose an intra-task DVS algorithm, which constructs a minimum energy schedule for k tasks in O(d+k log k) time We also give an inter-task DVS algorithm with O(d+n log n) time, where n denotes the number of jobs. Previous approaches solve this problem by generating a canonical schedule beforehand and adjusting the tasks' speed in O(dn log n) or O($n^3$) time. However, the length of a canonical schedule depends on the hyper period of those task periods and is of exponential length in general. In our approach, the tasks with arbitrary periods are first transformed into harmonic periods and then profile their key features. Afterward, an optimal discrete voltage schedule can be computed directly from those features.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1996.04a
• /
• pp.213-216
• /
• 1996

R'||'&'||'D project management is a process of decisions concerned with the achievement of goals of objectives. Especially, defense R'||'&'||'D project planning is the key in the successfull management of defense development. The defense project managers are constantly having to perform "what if\ulcorner" exercise, such as what if the project is extended out for an additional cost\ulcorner In this reserch, we developed a schedule-cost analysis model based upon Critical Path Method(CPM) and Venture Evaluation and Review Technique(VERT) for schedule-cost trade off analysis defense R'||'&'||'D projects. In the first step, a deterministic model is developed as a heuristic which deterministic model is developed as a heuristic which determines the schedule extension and reduction cost as a function desired schedule. In the second step, a stochastic network simulation model is developed to analyse the project risk (sucess and failure). The expected time and cost can be determined for desired schedule under the assumptions of stochastic arc data (time and cost) with a various precedence relationships. This model provides the defense R'||'&'||'D managers with an estimated and expected cost for curtailing or extending a project a given amount of time. The effectiveness and efficiency of the proposed methods, a heuristic and stochastic networks simulations, have been demonstrated through examples.

• Journal of the Korean Society for Railway
• /
• v.13 no.1
• /
• pp.23-30
• /
• 2010

In the construction phase, the existing schedule management system by 4D CAD has been difficult to check for a status and progress of construction product in real-time because it simulates only VR (virtual reality) object based on a planned schedule. This study suggests a construction schedule management system by telepresence technique that can visualize progress status in real-time by using 4D CAD system based on remote monitoring. The telepresence methodology and system were developed in the study and they were verified for a railway construction project. The developed system can examine the status and progress of construction because it can compare 4D simulation based on planned schedule with real-time site images through web-camera.

• 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.

• International conference on construction engineering and project management
• /
• 2017.10a
• /
• pp.8-13
• /
• 2017

Nuclear power plant (NPP) constructions are large scale projects that are executed for several years, and schedule control utilizing various schedules is a critically important factor. Recently Korea independently developed the Advanced Power Reactor (APR) 1400 and is building nuclear facilities applying this new reactor type. The construction of Shin-Kori NPP (SKN) Unit 3, which adopted the APR1400, was completed and commercial operation has begun, while, SKN 4, Shin-Hanul NPP (SHN) Units 1&2, and SKN 5&6 are currently under construction. Prior to the development of the APR1400, Korea built 24 reactors and accumulated the schedule data of various reactor types which provided the foundation for schedule reduction to be possible. However, as there is no schedule development and review system established based on the standard schedule data (standard activities, durations, etc.) by reactor type, the process for developing the schedule for new builds is low in efficiency consuming much time and manpower. Also all construction data has been accumulated based on schedule activities. But because the connectivity of activities between projects is low, it is difficult to utilize such accumulated data (causes for schedule delay, causes for design changes, etc.) in new build projects. Due to such reasons, issues continue to arise in the process of developing standard schedule activities and a standard schedule for nuclear power plant construction. In order to develop a standard schedule for NPP construction, i) the development of an NPP standard schedule activity list, ii) development of the connection logic of NPP standard schedule activities, iii) development of NPP standard schedule activity resources and duration, and iv) integration of schedule data need to be performed. In this paper, an analysis was made on the coherence of schedule activity descriptions of existing NPPs by applying the probabilistic methodology on activities with low connectivity due to the utilization of the numbering system of four APR1400 reactors (SHN 1&2 and SKN 3&4).This study also describes the method for developing a standard schedule activity list and connectivity measures by extracting same and/or similar schedule activities.