• 한국환경과학회지
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• 제24권5호
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• pp.647-655
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• 2015

In this study, to targeting Songpa of Seoul, were analyzed the effect on the noise mitigation in roadside buffer green spaces. Noise of Songpa Street buffer green space was determined to be higher during the day than at night. In addition, it was most of 60 db or more. However, the noise reduction function of the buffer green was not greatly affected by time. In the case of noise reduction rate, during the day time it was the order of the mounding type (18.14%)> plain type (5.73%)> slope type (4.08%), And, in the case of night time, it was the order of the mounding type (11.29%)> slope type (10.22%)> plain type (4.42%). Noise reduction rate, all of the daytime, was the highest in the mounding type. As a result of the factors on the amount of reduction of noise, More physical structure is mounding type, green structure is the stratification of green space, and the number of individuals is large, the higher the tree planting density, it is determined that the noise reduction effect is high. Also, factors affecting the noise reduction effect of the day and night were different.

• 대한인간공학회지
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• 제36권5호
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• pp.559-568
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• 2017

Objective: The aim of this study is to investigate the effective managerial factors influencing dose reduction of the nozzle dam installation and removal tasks ranking within top 3 in viewpoint of average collective dose of nuclear power plant maintenance job. Background: International Commission on Radiation Protection (ICRP) recommended to reduce unnecessary dose and to minimize the necessary dose on the participants of maintenance job in radiation fields. Method: Seven sessions of nozzle dam installation and removal task logs yielded a multiple regression model with collective dose as a dependent variable and work time, number of participants, space doses before and after shield as independent variables. From the sessions in which a significant reduction in collective dose occurred, the effective managerial factors were elicited. Results: Work time was the most important factor contributing to collective dose reduction of nozzle dam installation and removal task. Introduction of new technology in nozzle dam design or maintenance job is the most important factor for work time reduction. Conclusion: With extended task logs and big data processing technique, the more accurate prediction model illustrating the relationship between collective dose reduction and effective managerial factors would be developed. Application: The effective managerial factors will be useful to reduce collective dose of decommissioning tasks as well as regular preventive maintenance tasks for a nuclear power plant.

• 대한두개안면성형외과학회지
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• 제17권2호
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• pp.51-55
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• 2016

Background: Nasal bone fractures are managed by closed reduction within the 2-week period, and are managed by secondary correction after this time. There is little literature on the delayed reduction for nasal bone fractures beyond the 2-week duration. We report our experience with nasal fractures, which were reduced beyond this period. Methods: A retrospective review was performed for all patients who had undergone closed reduction of isolated nasal bone fracture. Patients were included for having undergone reduction of nasal bone fractures at or more than 2 weeks after the injury. Medical records were reviewed for demographic information, injury mechanism, fracture type, delay in treatment, and cause for delay. Postoperative outcomes were evaluated using computed tomography images. Results: The review identified 10 patients. The average reduction time was 22.1 days. Five of patients underwent reduction between days 15 and 20, and the remaining five patients underwent reduction between days 21 and 41. The postoperative outcomes were excellent in 8 patients and good in 2 patients. Conclusion: Outcomes were superior for nasal fractures with displaced end plates and multiple fracture segments. Our study results appears to support delayed reduction of isolated nasal fractures in the presence of factors that delay bony reunion.

• Nuclear Engineering and Technology
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• 제51권3호
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• pp.719-722
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• 2019

Gamma-ray images generally suffer from a lot of noise because of low photon detection in the gamma camera system. The purpose of this study is to improve the image quality in gamma-ray images using a gamma camera system with a fast nonlocal means (FNLM) noise reduction algorithm with an acceleration function. The designed FNLM algorithm is based on local region considerations, including the Euclidean distance in the gamma-ray image and use of the encoded information. To evaluate the noise characteristics, the normalized noise power spectrum (NNPS), contrast-to-noise ratio (CNR), and coefficient of variation (COV) were used. According to the NNPS result, the lowest values can be obtained using the FNLM noise reduction algorithm. In addition, when the conventional methods and the FNLM noise reduction algorithm were compared, the average CNR and COV using the proposed algorithm were approximately 2.23 and 7.95 times better than those of the noisy image, respectively. In particular, the image-processing time of the FNLM noise reduction algorithm can achieve the fastest time compared with conventional noise reduction methods. The results of the image qualities related to noise characteristics demonstrated the superiority of the proposed FNLM noise reduction algorithm in a gamma camera system.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2002년도 학술대회지
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• pp.316-322
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• 2002

근로시간이 단축될 경우 건설산업은 타산업과는 달리 일회성, 옥외성, 계절성 등의 특성으로 인하여 근로시간 단축으로 인한 파급효과를 단순히 작업의 총량개념으로만 접근하여 분석하기에는 어려움이 있다. 법정 근로시간 단축의 영향을 보다 정확하게 예측하기 위해서는 예상되는 비용상승 효과가 실제 건설공사 생산구조에 어떻게 받아들여질 것인가에 대한 조사와 분석이 필수적이다. 이를 위해 건설현장의 근로시간과 근로패턴에 관한 문헌조사와 일본 건설산업의 근로시간 단축 사례 조사를 수행하였으며, 결과적으로 근로시간 단축으로 인한 현장의 근로패턴 변화를 분석${\cdot}$ 예측하였다. 근로 패턴 변화는 실제 생산활동에 참여하는 현장근로자를 대상으로 년 단위 현행 모델과 근로시간 단축 후의 예측 모델을 구축하여 비교${\cdot}$분석하였으며, 현장관리 측면에서의 대처방안을 제시하였다.

• 한국건축시공학회지
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• 제10권5호
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• pp.87-94
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• 2010

건설공사는 현장을 중심으로 이루어지고 있어 공사계획초기 수립된 공기가 공기지연요인에 의하여 지연 또는 연장이 발생하게 되면 건설사는 클레임 등의 위험부담을 안고 있어 공기단축을 통해 공사 준공일 내에 목적물을 완공한다. 이에 광주광역시 내 공동주택 현장의 기술자들을 대상으로 공정관리 실태 및 공기단축의 필요성, 목적, 방법에 관한 인식을 파악해보았고 그 결과 타 지역에 비하여 공정관리전담부서 편성이 미흡하고 전문 인력이 부족함을 알았고, 공기단축의 필요성은 높게 인식된 반면 공사비 절감과의 관계는 낮게 인식되었다. 단축목적으로는 공기연장에 대비, 각종 클레임에 대처를 높게 인식하였으며 단축방법으로는 작업시간연장 및 작업원 증가를 통해 단축하겠다고 하였다. 이에 본 연구는 기술자들로 하여금 공기단축은 단순히 공기지연을 만회하기 위한 것이 아니라 원가절감을 통한 생산성 향상 및 대외 경쟁력 확보와 밀접한 관련성이 있다고 인식되어지길 기대한다.

• Smart Structures and Systems
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• 제14권6호
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• pp.1005-1030
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• 2014

The need for assessing dynamic response of typical industrial piping systems subjected to seismic loading motivated the authors to apply model reduction techniques to experimental dynamic substructuring. Initially, a better insight into the dynamic response of the emulated system was provided by means of the principal component analysis. The clear understanding of reduction basis requirements paved the way for the implementation of a number of model reduction techniques aimed at extending the applicability range of the hybrid testing technique beyond its traditional scope. Therefore, several hybrid simulations were performed on a typical full-scale industrial piping system endowed with a number of critical components, like elbows, Tee joints and bolted flange joints, ranging from operational to collapse limit states. Then, the favourable performance of the L-Stable Real-Time compatible time integrator and an effective delay compensation method were also checked throughout the testing campaign. Finally, several aspects of the piping performance were commented and conclusions drawn.

• 대한전자공학회논문지SP
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• 제42권3호
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• pp.121-128
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• 2005

음성신호를 대상으로 하는 연구 분야에서 신경회로망은 주로 음성인식 등의 카테고리 분류의 목적으로 사용되며 신호처리의 응용에도 유망하다. 따라서 본 논문에서는 신경회로망에 시간구조를 취한 시간지연 신경회로망을 이용하여 잡음이 중첩된 음성신호의 공간으로부터 잡음이 없는 음성신호의 공간으로 사상을 실행함으로써 잡음을 제거하는 것을 목적으로 한다. 본 논문은 푸리에 변환의 진폭성분을 복원하는 잡음제거의 알고리즘을 사용하여 백색잡음 및 유색잡음에 대해서 본 수법의 유효성을 확인한다.

• 응용통계연구
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• 제23권5호
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• pp.813-822
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• 2010

차원 축소(dimension reduction) 기법은 주로 횡단면 자료 분석에서 널리 이용되어 왔으며 시계열 분석 분야에서의 적용은 상대적으로 미진한 실정이다. 본 논문에서는 부분-수량화를 통한 주성분분석 방법을 계절형 시계열에 적용시켜 시계열 자료의 차원 축소를 시도하고자 한다. 분석 방법론을 단계별로 제시하였으며 월별 실업률 자료 분석을 통해 설명하였다.

• 한국물환경학회지
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• 제22권2호
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• pp.264-270
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• 2006

In this research, volume reduction of activated sludge using electrolysis was studied to find an optimum condition using lab scale experiments. Wasted sludge was treated by electrolysis with controlling current density, chloride concentration, electrode distance, and reaction time. Volume of return sludge was reduced by 9.79% in average while maximum was 16.7%. Sludge volume reduction efficiency was affected by current density and reaction time. It was reversely proportional to the electrode distance. Especially current density was effective on the system performance significantly. Electric conductivity, salinity and COD were increased by electrolysis implying sludge disintegrated and converted to COD in part. An empirical equation for total solid removal efficiency by electrolysis was proposed by multiple linear regression analysis as: $TS_{rem}$(%) = 5.534 ${\times}$ current density (A/l) + 0.178 ${\times}$ reaction time (m) + 2.758.