• 한국건설관리학회논문집
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• 제9권1호
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• pp.96-106
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• 2008

국내 CM은 2001년 건설산업기본법에 의해 개념과 범위가 정의된 후 지속적인 성장을 계속해 오고 있다. 하지만, 이러한 CM 제도에 기반한 성장에도 불구하고 국내에서의 CM 적용성과는 기대치에 비해 상대적으로 낮은 것으로 나타났다. 그 주요원인의 하나로 국내 CM제도가 책임감리에 비하여 업무범위가 넓지만, 대가기준은 책임감리에 비해 낮기 때문인 것으로 분석되었다. 따라서, 국내 CM 대가체계의 합리적인 기준을 정립하는 것이 시급할 것으로 판단된다. 본 연구에서는 CM 대가체계의 합리적인 기준을 마련하기 위하여 CMAA, ASCE, DOE, DOL 등의 다양한 해외사례 벤치마킹 연구를 통하여 국내 CM 대가체계를 비교하여 대가 상승요인을 추정하고 대가산정 개선방향을 제시하였다. 분석결과 대가수준은 해외에 비하여 현저하게 낮은 수준인 것으로 판단되었으며, 업무범위는 해외와 비교하여 그 폭이 좁으며 획일적인 구조를 가진 것으로 분석되었다. 따라서, 본 연구에서는 글로벌스탠다드에 따르는 국내 CM 대가체계를 개선하기 위하여 실비정액보수가산(Cost Plus Fixed Fee) 방식을 제시하고, 입 낙찰 전반에 걸친 CM 대가체계에 대한 기준(Framework)을 제시하였다.

• Journal of the Korean Wood Science and Technology
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• 제23권4호
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• pp.39-45
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• 1995

The plywoods commonly used as decorative interior materials for the construction are inflammable and so it is a causative factor for making fire accidents, resulting in the destruction of human life and personal properties. Indeed, it is, therefore, required to produce fire-retardant plywoods. In this study, a special grade of defect-free, Kapur plywood was used. Specimens were cut into 3- by 20cm dimensions from 120- by 240- by 0.33-cm panels(thin panel) or 120- by 240- by 0.5-cm panels(thick panel). Some specimens were treated with diammonium phosphate(DAP), but some were not treated with diammonium phosphate to use as control panels. Chemical absorption, drying curves, drying rates and dynamic Young's modulus were investigated. The results were summaries as follows; 1. The specimens were soaked into 19% diammonium phosphate solution by a full cell pressure process and the diammonium phosphate retained in the thin and thick plywoods was 1.409kg/$(30cm)^3$, 1.487kg/$(30cm)^3$, respectively. 2. Diammonium phosphate-treated plywoods were redried with press-drying process at one of either condition dried on the platen($115^{\circ}C$) for a period of time or dried on the platen($50^{\circ}C$) for 3 hrs plus in a dry-oven($30^{\circ}C$) for 24 hrs. or dried on the platen($60^{\circ}C$) for 2 hrs plus in a dry-oven($30^{\circ}C$) for 24 hrs. The drying rate of treated thin specimens dried at $60^{\circ}C$ plus $30^{\circ}C$ and $115^{\circ}C$ only was found to be 0.04 %/min. and 8.53 %/min. Similarly, the drying rate of treated thick specimens were 0.03 %/min. and 6.77 %/min. respectively. 3. It was evident that highly-significantly different drying rate of treated plywoods was observed between plywood thicknesses and platen temperatures and the rate was increased by elevating the platen temperature up to $115^{\circ}C$. Based on the two-way variance analysis, highly significant drying rate was observed from the interaction between plywood thicknesses and platen temperatures. 4. After redrying, the specimens were weighed and reconditioned to a constant weight in a facility maintained temperature ($20^{\circ}C$) and relative humidity(65%) prior to test dynamic Young's modulus. The test revealed that the thin specimens dried at the platen temperature of $50^{\circ}C$, $60^{\circ}C$, $115^{\circ}C$ and untreated specimens showed 1.070E+09 dyne/$cm^2$, 1.156E+09 dyne/$cm^2$, 1.243E+09 dyne/$cm^2$, and 1.052E+09 dyne/$cm^2$, respectively. Likewise, the thick specimens revealed 5.647E+09 dyne/$cm^2$ 5.670E+09 dyne/$cm^2$, 6.395E+09 dyne/$cm^2$ and 5.415E+09 dyne/$cm^2$, respectively. 5. It was evident that significantly different dynamic Young's modulus was observed between the plywood thickness and the platen temperature, but not in the two-way interaction between the plywood thickness${\times}$the platen temperature.

• 사물인터넷융복합논문지
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• 제9권3호
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• pp.27-33
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• 2023

본 연구에서는 Diospyros kaki Thunb(감)의 염색 패턴으로 분석하여 매염제에 따라 견직물과 세포의 염색 패턴이 어떻게 변화하는지 수치적으로 평가하고자 하였다. 염색된 견직물이 충분히 건조되었을 때 견직물은 엷은 황색을 띠는 것으로 나타났다. 흥미롭게도 철 II 황산염 매염제는 색 변화를 가장 많이 변화시켰고, 견직물은 갈색 또는 암자색에 가까운 색으로 염색되었다. 수치해석을 위해 타르타르산 나트륨과 구연산 및 아세트산 구리에의해 각각 19%와 62.5%의 색상 변화가 유도될 수 있었다. 철 II 황산염은 무처리 매염제보다 88%로 가장 큰 차이를 보였다. 중국 햄스터 난소(CHO) 세포의 약 5% 및 10%는 각각 타르타르산나트륨과 시트르산 및 아세트산구리로 염색되었다. 철 II 황산염에 의해 유도된 염색 효과는 타르타르산 나트륨 + 시트르산에 의한 염색 효과보다 약 2.4배 더 높았다. 기존의 연구들에서는 염색 결과를 육안적으로 확인하여왔다. 하지만, 본 논문의 결과들은 염색을 육안적으로 확인할 뿐만아니라 색상변화를 수치화한 것이다. 특히, 빅데이터에 수치화된 결과들이 계속 집약 된다면 방법에서, 시간, 부피 등을 변화시키더라도 유사한 결과들을 어느 연구자들이 쉽게 얻을 수 있을 것이다. 또한, 본 연구의 수치 데이터는 IoT 구축 및 컴퓨터 분석을 위한 데이터베이스 구축에 중요한 근거가 될 수 있을 것으로 사료된다.

• 한국산림과학회지
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• 제42권1호
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• pp.74-82
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• 1979

우리나라 소나무 수형목(秀型木)에 대(對)한 연령별(年齡別) 수고변화(樹高變化), 유전력(遺傳力), 및 개량효과(改良効果)를 조사(調査)하였는데 그 결과(結果)를 요약(要約)하면 다음과 같다. 1. 가계별(家系別) 수고생장(樹高生長) 순위변화(順位變化)를 조사(調査)한 결과(結果) 3년생(年生)까지는 비교적(比較的) 순위변화(順位變化)가 심(甚)하게 나타나며 입지조건(立地條件)이 불리(不利)한 곳에서는 더욱 심(甚)한 변화(變化)를 나타냈다. 2. 수고유전력(樹高遺傳力)을 연령별(年齡別)로 조사(調査)한 결과(結果) 3년생(年生)은 7.2%, 4년생(年生)은 (-)값을 보였으며, 5년생(年生)은 9.4%, 6년생(年生)은 13.0%, 7년생(年生)은 8.1%, 8년생(年生)은 63.8%로 나타나 대체적(大體的)으로 연령(年齡)의 증가(增加)에 따라 증가(增加)하는 경향(傾向)을 보였다. 3. 근원경(根元徑) 및 가지 직경(直徑)의 유전력(遺傳力)은 8년생(年生)에서 각각(各各) 3.2%, 11.8%이었다. 4. 개량효과(改良効果)를 측정(測定)한 결과(結果) 8년생(年生)에서 선발강도(選拔强度)를 1/500로 볼 때 46.6%로서 가장 높은 값을 보였으므로 7년생이하(年生以下)에서는 선발(選拔)을 실시(實施)하지 않는 것이 좋을 것으로 사료(思料)된다.

• 한국건설관리학회논문집
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• 제11권2호
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• pp.94-105
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• 2010

최근 도시내 기반시설이 노후화된 불량지구에 거주하는 사회적 약자(저소득층, 도시빈곤층)가 도시재생과정에서 지불능력한계 등에 의하여 재정착하지 못하고 있는 문제는 사회적 이슈로 부각되고 있다. 이에 본 연구에서는 사회적 약자의 재정착을 위한 방안 중 하나로 '입찰가격 최적화 및 생산비용 절감', '공기단축을 통한 비용절감', '적정 품질 만족'을 목적으로 한 '최저통합환산가격(입찰가격+공사기간환산가격) 개념의 기술제안 기반 입찰제도'를 제시하였으며, 이는 프로젝트단위 기술제안, 공종단위 기술제안, 공기단축 기술제안을 기반으로 이루어진다. 본 연구에서 제안한 최저통합환산가격 개념의 기술제안 기반 입찰제도는 공기단축에 의한 추가적인 인력 및 장비의 투입과 품질향상 등에 의하여 직접비는 상승되나 공기단축에 의한 발주자 비용, 감리비, 원주민 보상비에 대한 이자비용, 간접비, 이자 지급비, 물가 상승비 등의 절감이 기대된다. 이와 더불어 공기단축 및 공사비 절감 관련 기술 지식의 축적은 향후 프로젝트 공사비 및 공사기간 최적화가 가능함은 물론 국가 및 기업 경쟁력 향상이 기대된다.

• 설비공학논문집
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• 제28권3호
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• pp.110-114
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• 2016

Newly constructed multi-residential buildings with more than 500 households should be flushed out indoor contaminants using a mechanical ventilation system or large fans after the completion of construction and prior to occupancy by the Heath-friendly Housing Construction Standards since 2014. In addition, the standard recommends to maintain indoor temperature over $16^{\circ}C$ and relative humidity below 60% while performing the flush-out. However, it is difficult to maintain these recommended indoor conditions, especially during winter season because additional energy cost is needed for space heating. Therefore, in this study, additional energy cost including heating and ventilation energy cost in multi-residential household for flush-out during winter season was estimated using building energy simulation program called EnergyPlus. Additional energy cost according to various conditions for performing flush-out (such as performance period, ventilation rate, and heating set-point temperature) was analyzed. Based on the results of the energy simulation, the energy cost was estimated to be ranged from 14,625 to 29,452\/household in Incheon city and from 3,521 to 26,268\/household in Gwangju City. There was no significant change in energy cost according to the performing terms of flush-out between Incheon and Gwangju City.

• Nuclear Engineering and Technology
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• 제51권3호
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• pp.709-718
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• 2019

The international nuclear industry has undergone a lot of changes since the Fukushima, Chernobyl and TMI nuclear power plant accidents. However, there are still large and small component deficiencies at nuclear power plants in the world. There are many causes of electrical equipment defects. There are also factors that cause component failures due to human errors. This paper analyzed the root causes of failure and types of human error in 300 cases of electrical component failures. We analyzed the operating experience of electrical components by methods of root causes in K-HPES (Korean-version of Human Performance Enhancement System) and by methods of human error types in HuRAM+ (Human error-Related event root cause Analysis Method Plus). As a result of analysis, the most electrical component failures appeared as circuit breakers and emergency generators. The major causes of failure showed deterioration and contact failure of electrical components by human error of operations management. The causes of direct failure were due to aged components. Types of human error affecting the causes of electrical equipment failure are as follows. The human error type group I showed that errors of commission (EOC) were 97%, the human error type group II showed that slip/lapse errors were 74%, and the human error type group III showed that latent errors were 95%. This paper is meaningful in that we have approached the causes of electrical equipment failures from a comprehensive human error perspective and found a countermeasure against the root cause. This study will help human performance enhancement in nuclear power plants. However, this paper has done a lot of research on improving human performance in the maintenance field rather than in the design and construction stages. In the future, continuous research on types of human error and prevention measures in the design and construction sector will be required.

• Journal of electromagnetic engineering and science
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• 제6권2호
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• pp.83-91
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• 2006

In this paper, we develop space-time(ST) Rake receivers for Time Division Synchronous Code Division Multiple Access(TD-SCDMA) base stations(BS). The beamforming of BS transforms the uplink MIMO channel space into many sub-sectors' channels to be nearly orthogonal, thus, well established 1-D Rake technology can be used to TD-SCDMA base station to construct ST Rake, which simplified the system's implementation as well as enlarged users' capacity by the beamforming. The construction and capacity of MIMO sub-sectors by multi-beamforming have been presented. The proposed ST Rake algorithm include the multi-beamforming algorithm for MIMO sub-sectors and classical 1-D Rake algorithm. The calculating formulas for interference plus noise ratio(SINR) and bit error rate(BER) have been derived. Simulations verify that the proposed ST Rake receiver for BS is effective, and the BS systems can get higher system capacity and can be of better performance than presented TD-SCDMA systems.

• Structural Engineering and Mechanics
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• 제50권3호
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• pp.323-347
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• 2014

This paper proposes a Particle Swarm Optimization (PSO) algorithm, which is improved by making use of the Harmony Search (HS) approach and called HS-PSO algorithm. A computer code is developed for optimal sizing design of non-linear steel frames with various semi-rigid and rigid beam-to-column connections based on the HS-PSO algorithm. The developed code selects suitable sections for beams and columns, from a standard set of steel sections such as American Institute of Steel Construction (AISC) wide-flange W-shapes, such that the minimum total cost, which comprises total member plus connection costs, is obtained. Stress and displacement constraints of AISC-LRFD code together with the size constraints are imposed on the frame in the optimal design procedure. The nonlinear moment-rotation behavior of connections is modeled using the Frye-Morris polynomial model. Moreover, the P-${\Delta}$ effects of beam-column members are taken into account in the non-linear structural analysis. Three benchmark design examples with several types of connections are presented and the results are compared with those of standard PSO and of other researches as well. The comparison shows that the proposed HS-PSO algorithm performs better both than the PSO and the Big Bang-Big Crunch (BB-BC) methods.

• 한국멀티미디어학회논문지
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• 제13권6호
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• pp.849-864
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• 2010

This paper proposes a multipath routing protocol called cross-layer multipath AODV (CM-AODV) for wireless ad hoc networks, which selects multiple routes on demand based on the signal-to-interference plus noise ratio (SINR) measured at the physical layer. Note that AODV (Ad hoc On-demand Distance Vector) is one of the most popular routing protocols for mobile ad hoc networks. Each time a route request (RREQ) message is forwarded hop by hop, each forwarding node updates the route quality which is defined as the minimum SINR of serialized links in a route and is contained in the RREQ header. While achieving robust packet delivery, the proposed CM-AODV is amenable to immediate implementation using existing technology by neither defining additional packet types nor increasing packet length. Compared to the conventional multipath version of AODV (which is called AOMDV), CM-AODV assigns the construction of multiple paths to the destination node and makes it algorithmically simple, resulting in the improved performance of packet delivery and the less overhead incurred at intermediate nodes. Our performance study shows that CM-AODV significantly outperforms AOMDV in terms of packet delivery ratio and average end-to-end delay, and results in less routing overhead.