• 국제학술발표논문집
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• The 2th International Conference on Construction Engineering and Project Management
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• pp.520-529
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• 2007

Apportioning responsibilities of concurrent delay to the owner and the contractor is a difficult task, due to the sophisticate nature both in the schedule and in the factors that cause the delay. This research attempts to develop a simplified yet systematic approach that can be used for a fair apportionment of concurrent delay. A concurrent delay is defined herein as when the contractor and the owner have both caused independent critical path delays during the same approximate time period. Incorporating the concepts of windows analysis and critical path method (CPM), the developed approach has three "windowing of delay" steps to quickly apportion the delay in each of these windows, and a fourth step to sum up those apportioned delays to obtain each party's final responsibilities. This developed approach is found to be simple and effective at this stage; it will be tested against real cases in the near future.

• 전기학회논문지P
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• 제63권2호
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• pp.81-88
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• 2014

In this paper, an implementation of concurrent backoff delay process on a single chip with IEEE 802.15.4 hardware and 8051 processor core that can be used for analyzing the interference on IEEE 802.15.4 channels due to WiFi traffics is studied. The backoff delay process of IEEE 802.15.4 CSMA-CA algorithm is explained. The characteristics of random number generator, timer, and CCA register included in the single chip are described with their control procedure in order to implement the process. A concurrent backoff delay process to evaluate multiple IEEE 802.15.4 channels is proposed, and a method to service the associated tasks at sequentially ordered backoff delay events occurring on the channels is explained. For the implementation of the concurrent backoff delay process on a single chip IEEE 802.15.4 hardware, the elements for the single channel backoff delay process and their control procedure are used to be extended to multiple channels with little modification. The medium access delay on each channel, which is available after execution of the concurrent backoff delay process, is displayed on the LCD of an IEEE 802.15.4 channel analyzer. The experimental results show that we can easily identify the interference on IEEE 802.15.4 channels caused by WiFi traffics in comparison with the way displaying measured channel powers.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2003년도 학술대회지
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• pp.438-441
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• 2003

건설 산업 대부분의 프로젝트에서 공기지연의 발생은 매우 일반적이나 CPM, Bar Chart와 같은 지연분석 기법들로서는 분석하기 매우 어렵다. CPM과 Bar chart를 이용하는 분석기법들은 동시발생과 생산성 손실 지연을 분석하기에 불충분하기 때문이다. 생산성 손실 지연은 동시발생 지연 분석 및 지연 일수 산정에서 중단으로 인한 지연과 다르게 분석되어야 한다. 본 논문에서는 동시발생 공기지연 분석을 포함하여 생산성을 고려한 공기지연 분석방법에 대하여 논하였다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 추계 학술논문 발표대회
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• pp.68-69
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• 2015

Traditional External Insulation Finishing System(EIFS) is applied to apartment construction by performing structural framework and insulation finishing work sequentially. Separate execution of the three works increases construction cost and duration. Concurrent construction method of EIFS, which performs framework and insulation finishing work simultaneously, is introduced in order to solve these problems. However, the introduced method is exposed to the risk of construction delay caused by bottlenecks due to interacting processes and resources. Therefore, this paper presents a simulation model suitable for estimating work productivity of the concurrent construction by considering predecessor and successor processes to optimize resource allocation and minimize construction delay.

• 대한전기학회논문지:전력기술부문A
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• 제48권10호
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• pp.1344-1348
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• 1999

This paper proposes concurrent event propagation technique for timing analysis. The technique makes it possible to find several input vectors and sensitizable paths at the same time. The concurrent event propagation technique is based on the event driven simulation and the timing analysis technique with boolean equations. The technique propagates as many events as possible at the same time while preventing propagation of boolean terms which do not sensitize paths. Since events do not propagate through false paths, the longest path which successfully propagates events to one of the primary outputs is one of the longest sensitizable paths. The technique can speed up timing analysis by unifying path sensitization and maximum delay calculation.

• 한국정보처리학회논문지
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• 제5권11호
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• pp.2989-2996
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• 1998

집적회로의 집적도가 높아지고 성능이 향상됨에 따라 회로의 지연고장에 대한 관심이 날로 높아지고 있다. 회로의 지연고장은 게이트 지연고장과 경로지연고장으로 분류할 수 있는데, 이 논문에서는 경로지연고장 시뮬레이션에 대한 두 가지 동적 메모리 사용 방법을 제안하였다. 첫 번째 방법은 고착고장에 대한 동시 고장 시뮬레이션과 유사한 방식이며, 두 번째 방법은 고장기술자의 값이 X일 때 이를 고장리스트에 삽입하지 않는 묵시적-X 방식이다. 제안된 두 방식 중 묵시적-X 방식이 동적 메모리 사용과 시뮬레이션 시간 측면에서 효율적이었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권6호
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• pp.2870-2888
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• 2017

Recent studies have shown that the flow table size of hardware SDN switch cannot match the number of concurrent flows. Combined SDN Forwarding Element (CFE), which comprises several software switches and a hardware switch, becomes an alternative approach to tackle this problem. Due to the limited capacity of software switch, the way to route concurrent flows in CFE can largely affect the maximum delay that a flow suffers at CFE. As delay-guarantee is a nontrivial task for network providers with the increasing number of delay-sensitive applications, we propose an analytical model of CFE to evaluate a rules placement solution first. Next, we formulate the problem of Rules Placement with delay guarantee in CFE (RPCFE), and present the genetic-based rules placement (GARP) algorithm to solve the RPCFE problem. Further, we validate the analytical model of CFE through simulations in NS-3 and compare the performance of GARP with three benchmark algorithms.

• 한국건설관리학회논문집
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• 제24권1호
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• pp.12-20
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• 2023

국내에서 관행적으로 사용되어온 간편법에 의한 공기지연 분석시 발주자와 계약자의 지연일수 산정은 동시발생 공기지연의 영향과 돌관공사의 수행의 영향을 반영하지 못하는 한계가 있으며, 양 당사자에 대한 지체상금의 부과에 있어서도 문제를 가져왔다. 본 연구에서는 지체상금에 대한 국제 판례를 분석하고, 발주자와 계약자의 지연일수의 비율을 적용하여 지체상금을 부과하는 기존 방식의 문제점을 국제 기준과 비교하여 분석되었다. 공기지연 분석의 문제점과 이를 기반으로 한 지체상금 산정의 문제점을 개선하기 위해서는 공기지연 분석에 있어서 발주자 지연, 계약자 지연, 동시발생 공기지연을 분석하고, 돌관공사의 영향을 고려한 종합적인 공기지연에 대한 귀책 분석이 필요하며, 지체상금의 부과에 있어서 발주자의 귀책에 의한 지연일수와 동시발생 공기지연 일수를 합한 기간 만큼 준공기한을 연장하고, 그 이후에 발생된 지연에 대하여 지체상금을 부과하는, 국제기준에 부합하는 지체상금 부과 방안을 제시하였다. 본 연구의 결과는 기존 관행적으로 수용되어 오던 실무 공기지연분석 및 지체상금 산정의 문제점을 개선하는데 기여할 수 있을 것으로 기대된다.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• 제33권1호
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• pp.16-23
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• 2022

Objectives: Early detection of developmental issues in infants and necessary intervention are important. To identify the comorbid conditions, a comprehensive evaluation is required. The study's objectives were to 1) generate scale items by identifying and eliciting concepts relevant to young children (12-71 months) with developmental delays, 2) develop a comprehensive screening tool for developmental delay and comorbid conditions, and 3) assess the tool's validity and cut-off. Methods: Multidisciplinary experts devised the "Infant Comprehensive Evaluation for Neurodevelopmental Delay (ICEND)," an assessment method that comes in two versions depending on the age of the child: 12-36 months and 37-71 months, through monthly seminars and focused group interviews. The ICEND is composed of three parts: risk factors, resilience factors, and clinical scales. In parts 1 and 2, there were 41 caretakers responded to the questionnaires. Part 3 involved clinicians evaluating ten subscales using 98 and 114 questionnaires for younger and older versions, respectively. The Child Behavior Checklist, Strengths and Difficulties Questionnaire, Infant-Toddler Social Emotional Assessment, and Korean Developmental Screening Test for Infants and Children were employed to analyze concurrent validity with the ICEND. The analyses were performed on both typical and high-risk infants to identify concurrent validity, reliability, and cut-off scores. Results: A total of 296 people participated in the study, with 57 of them being high-risk (19.2%). The Cronbach's alpha was positive (0.533-0.928). In the majority of domains, the ICEND demonstrated a fair discriminatory ability, with a sensitivity of 0.5-0.7 and specificity 0.7-0.9. Conclusion: The ICEND is reliable and valid, indicating its potential as an auxiliary tool for assessing neurodevelopmental delay and comorbid conditions in children aged 12-36 months and 37-71 months.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권3호
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• pp.778-798
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• 2014

This paper proposes a novel exposed-terminal-eliminated medium access control (ETE-MAC) protocol by combining channel reservation, collision avoidance and concurrent transmissions to improve multi-access performance of the multihop wireless networks. Based on the proposed slot scheduling scheme, each node senses the control channel (CCH) or the data channel (DCH) to accurately determine whether it can send or receive the corresponding packets without collisions. Slot reservation on the CCH can be simultaneously executed with data packet transmissions on the DCH. Therefore, it resolves the hidden-terminal type and the exposed-terminal type problems efficiently, and obtains more spatial reuse of channel resources. Concurrent packet transmissions without extra network overheads are maximized. An analytical model combining Markov model and M/G/1 queuing theory is proposed to analyze its performance. The performance comparison between analysis and simulation shows that the analytical model is highly accurate. Finally, simulation results show that, the proposed protocol obviously outperforms the link-directionality-based dual-channel MAC protocol (DCP) and WiFlex in terms of the network throughput and the average packet delay.