• The Journal of the Acoustical Society of Korea
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• 제24권3E호
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• pp.87-89
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• 2005

The acoustical sources of intake and exhaust systems in fluid machines are often characterized by the source impedance and strength using linear frequency-domain modeling. In the case of the sources which are nonlinear and time-variant, however, the source parameters were sometimes incorrectly obtained. In this paper, the source model and direct measurement technique are modified in order to evaluate the effect due to nonlinear and periodically time-varying source character as well as the linear property of the reflectivity of in-duct fluid machine source. With a priori known kinematical information of the source, the types of nonlinear time-variant terms can be presumed by a simple physical model, in which there is practically no restriction on the form of the model. The concept of source impedance can be extendable by introducing the linear frequency response function for each nonlinear or time-variant input. Extending the conventional method and adapting the reverse MISO technique, it is possible to develop a direct method that can deal with the nonlinear time-variant source parameters. The proposed direct method has a novel feature that there is no restriction on the probability or spectral natures of the excited sound pressure data. The present method is verified by the simulated measurements for simplified fluid machines. It is thought that the proposed method would be useful in predicting the insertion loss or the radiated sound level from intake or exhaust systems.

• 정보처리학회논문지D
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• 제16D권1호
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• pp.73-82
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• 2009

오픈소스 소프트웨어는 응용 소프트웨어 개발의 60% 이상을 차지하고 있으나 이를 활용하기 위한 객관적인 품질 모델이나 지표에 대한 연구가 초보적인 수준에 머물고 있으며, 이를 평가하기 위한 정량적인 평가 기법에 대한 연구도 거의 이루어지고 있지 않다. 본 연구는 응용 소프트웨어 개발 및 유지보수에 활용할 수 있는 품질평가 모델을 제시하고, 제시된 품질평가 모델에서 활용할 수 있는 정량적 품질 평가 기법을 제시한다. 제안한 오픈소스 소프트웨어 품질 모델은 문헌 자료를 기반으로 품질 특성을 도출하고, 이를 ISO 9126의 품질 특성과 비교 검토하여 6개의 주특성과 12개의 부특성과 이를 정략적으로 측정할 수 있는 12개의 평가 메트릭으로 구성된 '논리적 오픈소스 소프트웨어 품질 모델'을 제안하였다. 제안한 품질 평가 모델의 효율성을 검증하기 위하여 오픈소스 소프트웨어 커뮤니티에 있는 상위 Rank 5개의 프로젝트 관리 시스템(PMS) 관련 소프트웨어를 대상으로 제안한 품질평가을 적용하여 그 가능성을 입증하였다.

• 컴퓨터교육학회논문지
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• 제18권4호
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• pp.63-70
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• 2015

프로그램 소스코드는 텍스트를 기반으로 하는 정보이며 동시에 논리 구조를 포함하고 있는 복잡한 구문의 집합체이다. 특히 소스코드의 규모가 수만 라인에 이르는 경우 구조적, 논리적인 복잡함으로 인해 기존의 빅데이터 시각화 기법이 잘 적용되기 힘들다는 문제가 발생한다. 본 논문은 소스코드가 갖는 구조적인 특징을 시각화하는데 있어 필요한 절차를 제안한다. 이를 위해 본 논문은 파싱 과정을 거쳐 생성된 추상구문트리를 대상으로 프로그램의 구조특징을 표현하기 위한 자료형의 정의, 함수간 호출관계를 표현한다. 이들 정보를 바탕으로 제어 정보를 네트워크 형태로 시각화함으로써 모듈의 구조적인 특징을 개괄적으로 살펴볼 수 있는 방법을 제시한다. 본 연구의 결과는 대규모 소프트웨어의 구조적 특징을 이해하거나 변경을 관리하는 효과적인 수단으로 활용할 수 있다.

• Korean Journal of Acupuncture
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• 제38권2호
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• pp.100-109
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• 2021

Objectives : Source acupoint is one of the representative acupoints to treat various diseases in each meridian. We aimed to identify the patterns of selection of Source acupoints and their associations with diseases using clinical trials data. Methods : We extracted the frequency of Source acupoints across 30 diseases from clinical trials database. Acupuncture treatment regimens were retrieved from the Cochrane Database of Systematic Reviews. The frequency of Source acupoint use was calculated as the number of studies using a certain acupoint divided by the total number of included studies. Using hierarchical clustering and multidimensional scaling, the characteristics of Source acupoints were analyzed based on the similarity of the relationships between the Source acupoints and the diseases. Results : A total of 421 clinical trials were included for this analysis. LR3, HT7, KI3, and LI4 acupoints were most frequently used for the treatment of 30 diseases. Cluster analysis showed that LR3 and LI4 acupoints were grouped together and HT7 and KI3 acupoints were grouped together. Multidimensional scaling revealed that LR3, LI4, HT7, and KI3 acupoints have intrinsic properties in the two-dimensional space. Conclusions : The present study identified the selection patterns of the Source acupoints using clinical trials data. Our finding will provide the understanding of the characteristics of Source acupoints.

• KIEAE Journal
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• 제14권1호
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• pp.39-48
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• 2014

In the previous test, the verification of the standard floor impact source was carried out comparing the physical characteristics with living impact sources. The result was appeared the validation of the standard impact source was very low because of differences of physical characteristics. This study aims to evaluate annoyance and loudness of standard impact source which is used for the measurement of floor impact sound, and to compare the annoyance and loudness of living impact sources which are produced in real life. The impact sources considered are tapping machine, tire and impact ball as standard sources, and nine real sources which were chosen from the existing researches. The result showed differences of annoyance and loudness between standard impact sources and living impact sources, which means the standard impact sources may rate the performance of floor system inappropriately. In the future, the rating method should be examined how the standard impact sources are similar with real sources in the point of rating the performance of floor system.

• 전기학회논문지
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• 제58권1호
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• pp.42-48
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• 2009

Microgrid supplies loads with power interconnected grid. And it is defined a independent power system compounded micro sources over two devices which have enough capacity to operate independently, storage devices and loads. The energy sources of micro source have different dynamic characteristics corresponding to classes and application skills. However their transient responses are various from a few seconds to minutes. Therefore it is limitation for understanding operation characteristics of microsource modeling constant voltage source or constant current source. This paper shows that we designed EMTP/RV model of micro source which is microturbine based energy source. And we performed dynamic analysis of micro source corresponding to operation mode of microgrid.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.1069-1077
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• 2009

For external noise prediction of railway vehicles, sophisticated individual source modelling as well as appropriate noise propagation model from the sources is necessary to ensure the accuracy of the predicted results and contributions of each equipment to the overall noise levels. Accurate and reasonable identification procedures of sound sources of equipment including source strength, directivity and positions installed in the train play an important role in a prediction model, since it is not easy to establish a simple model for the sources with a single rule due to the complexity of source characteristics of equipment in size and directivity pattern. This paper guidelines practical considerations for identification of noise sources in railway vehicles including typical source characteristics of several sub-systems that emits noise to the environment, particularly for electric multiple unit(EMU), and verify effectiveness of assumptions used in the modelling of equipment by measurement with a simple part. The predicted external noise level of a complete train using Exnoise, which was developed by Hyundai-Rotem and has been verified in the a lot of field-tests, incorporating source modelling considered in this paper shows close correlation with the measured ones.

• 한국지열·수열에너지학회논문집
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• 제8권2호
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• pp.9-15
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• 2012

The objective of this study is to investigate the influence on the heating performance for a water-to-water 10RT ground source heat pump by using the water switching and refrigerant switching method. The test of water-to-water ground source heat pump was measured by varying the compressor speed, load side inlet temperature, and ground heat source side temperature. The heating capacity and COP of the heat pump increased with increasing ground heat source temperature. As a result, compared to a refrigerant switching method, the water switching method with counter flow improves the heating capacity and COP by approximately 5% in average, respectively.

• 한국소음진동공학회논문집
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• 제16권8호
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• pp.789-796
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• 2006

The characteristics of the four standard floor impact sources (impact ball, bang machine, tapping machine, modified tapping machine) and a human impact source (jumping children) were investigated. First, the mechanical impedance of each source were evaluated. Then, the impact force exposure level of each source were measured. The results showed that fundamental frequency and impedance produced by the impact ball are the most similar to those of the human impact source. The frequency characteristics of the impact ball were most similar to those of jumping children. Consequently, the impact ball more accurately reproduces human impact compared to the other standard impact sources. Therefore, the impact ball should be considered as the reliable impactor in evaluating floor impact noise.

• Nuclear Engineering and Technology
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• 제54권9호
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• pp.3478-3487
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• 2022

In this study, we incorporate an anisotropic scattering scheme involving spherical harmonics into the method of characteristics (MOC). The neutron transport solution in a light water reactor can be significantly improved because of the impact of an anisotropic scattering source with the MOC flat source approximation. Several problems are selected to verify the proposed scheme and investigate its effects and accuracy. The MOC anisotropic scattering source is based on the expansion of spherical harmonics with Legendre polynomial functions. The angular flux, scattering source, and cross section are expanded in terms of the surface spherical harmonics. Later, the polynomial is expanded to achieve the odd and even parity of the source components. Ultimately, the MOC angular and scalar fluxes are calculated from a combination of two sources. This paper presents various numerical examples that represent the hot and cold conditions of a reactor core with boron concentration, burnable absorbers, and control rod materials, with and without a reflector or baffle. Moreover, a small critical core problem is considered which involves significant neutron leakage at room temperature. We demonstrate that an anisotropic scattering source significantly improves solution accuracy for the small core high-leakage problem, as well as for practical large core analyses.