• 설비공학논문집
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• 제15권7호
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• pp.579-585
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• 2003

The ejector system is used for making a vacuum in an enclosed tank. This research represents the method to improve ejector performance by inserting a strut at the center of ejector outlet. This proposed ejector system is so simple and have a low cost to improve the ejector performance. There are many kinds of method for obtaining a lower vacuum pressure. The ejector is consists of nozzle, straight pipe and outlet diffuser and we focused on the outlet diffuser for high ejector performance. The strut is located at the center of ejector outlet diffuser. As the experimental result, we compared the vacuum pressure with and without a strut and without strut, and the ejector performance showed an improvement with 40% or more than the case without strut. This means that the stable fluid low energy loss was obtained by inserting the strut.

• 산업경영시스템학회지
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• 제34권4호
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• pp.42-48
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• 2011

This paper proposes performance measurement method of quality small-group activity in business. This paper collects and analyzes quality circle activities data respect to tangible and intangible effect in national quality circles competitions festival. This paper proposes QPI (quality-circle performance index) based on Balanced Scorecard for quality small-group activity in quality improvement area. QPI is to measure the performance of quality improvement activities in the business firms. QPI is able to use widely in industries to provide a performance measure of quality small-group activity. In this paper, we propose the application method of QPl.

• 한국안전학회지
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• 제35권3호
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• pp.43-48
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• 2020

It is considered that most of reusable pipe supports, which are used as formwork support posting at construction sites, do not meet the performance standard. Due to the use of reusable pipe supports that do not meet such performance standard the potential risk of collapse accident is increasing. Therefore, this study identifies the status of compliance with performance standard, and presents the requirements for improving quality control to prevent the collapse of pipe supports reused at the construction site. First, if the female thread of the product with no clearance and new support pin with the diameter of 12mm are replaced at the same time for use, it is considered that the performance will be improved. Second, as the quality performance during use can be improved in the case of larger thickness of inner diameter compared to the case of larger thickness of outer diameter, it is necessary to increase the inner pipe thickness greatly than the current thickness. Based on the results of this study, it is expected that the performance the reusable pipe support (V4) can be improved, if the diameter of the support pin is 12mm, the female thread has a small clearance, and the inner tube thickness is 2.3 ~ 2.7mm. In addition, it is considered that other performance improvement factors included in the study results could be used as important data for improving the performance of reusable pipe support.

• 한국항만경제학회지
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• 제34권3호
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• pp.75-92
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• 2018

본 연구의 목적은 물류기업의 혁신활동이 혁신성과와 서비스품질의 개선에 영향을 미치는지 여부와 혁신활동을 통해 창출된 혁신성과와 서비스품질이 물류기업의 경영성과에 영향을 미치는지를 분석하는데 있다. 우선 혁신활동, 혁신성과에 관련된 이론과 선행연구를 분석하였다. 그리고 혁신성과와 함께 서비스품질의 개선에 관한 선행연구들도 분석하였다. 이를 근거로 연구모형과 가설을 설정하였다. 이를 분석하기 위해, 한국노동연구원의 사업체패널 자료를 활용했고, 총 88개의 샘플을 사용하였다. 이를 바탕으로 구조방정식 분석을 위해 PLS를 이용하였다. 실증분석 결과, 물류기업의 혁신활동은 혁신성과와 서비스품질개선의 긍정적인 영향을 미쳤으며, 혁신성과와 서비스품질은 재무성과에 긍정적인 영향을 미치는 것으로 나타났다. 결과적으로 물류기업에게 혁신활동은 물류기업에게 뚜렷한 경쟁우위를 가져다주고, 서비스품질의 개선을 가져다주게 된다. 이는 물류기업이 경쟁에서 승리하고 생존하기 위해서는 꾸준한 혁신활동이 필요하다는 것을 실증적으로 보여주었다.

• 대한임베디드공학회논문지
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• 제18권3호
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• pp.89-100
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• 2023

Recently, on-device artificial intelligence (AI) solutions using mobile devices and embedded edge devices have emerged in various fields, such as computer vision, to address network traffic burdens, low-energy operations, and security problems. Although vision transformer deep learning models have outperformed conventional convolutional neural network (CNN) models in computer vision, they require more computations and parameters than CNN models. Thus, they are not directly applicable to embedded edge devices with limited hardware resources. Many researchers have proposed various model compression methods or lightweight architectures for vision transformers; however, there are only a few studies evaluating the effects of model compression techniques of vision transformers on performance. Regarding this problem, this paper presents a performance evaluation of vision transformers on embedded platforms. We investigated the behaviors of three vision transformers: DeiT, LeViT, and MobileViT. Each model performance was evaluated by accuracy and inference time on edge devices using the ImageNet dataset. We assessed the effects of the quantization method applied to the models on latency enhancement and accuracy degradation by profiling the proportion of response time occupied by major operations. In addition, we evaluated the performance of each model on GPU and EdgeTPU-based edge devices. In our experimental results, LeViT showed the best performance in CPU-based edge devices, and DeiT-small showed the highest performance improvement in GPU-based edge devices. In addition, only MobileViT models showed performance improvement on EdgeTPU. Summarizing the analysis results through profiling, the degree of performance improvement of each vision transformer model was highly dependent on the proportion of parts that could be optimized in the target edge device. In summary, to apply vision transformers to on-device AI solutions, either proper operation composition and optimizations specific to target edge devices must be considered.

• 지식경영연구
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• 제10권1호
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• pp.71-100
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• 2009

Recently, many of organizations build up their performance measurement system (PMS) to measure their knowledge management performance. However, the system that doesn't well reflect the organization's strategies as well as surroundings could obstruct their performance improvement, instead. Therefore, It is really important to establish the PMS to reflect organization's surroundings and strategies. The purpose of this study is to make a diagnosis of a performance measurement practice of a domestic university's knowledge management. To serve this research purpose, we examine the uptight performance index and PMS from existing references. And we diagnose the specific practices and maturity rates of measuring performances, and the recognition of the performance index at "D" university recently adopting balanced scorecard to performance evaluation through the survey on academic affairs committee members, performance evaluation committee members, and administration members. The method analyzing data from the survey is a gap analysis which includes alignment analysis, congruence analysis, consensus analysis, and confusion analysis. We make a diagnosis of performance measurement practices at "D" university, raise several points of this performance measurement system, and present the improvement plans from these problems.

• 한국유체기계학회 논문집
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• 제9권3호
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• pp.29-35
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• 2006

There are high expectations of improving the performance of a centrifugal pump in the range of very low specific speed which has been developed recently for the use instead of a conventional positive displacement pump. However, even though elaborated studies has been done for the pump intensively, the pump performance has not increased so much. Also, it is difficult to find detailed information from published literatures for suction performance of the very low specific speed centrifugal pump. Therefore, this study is aimed to improve the pump performance more and to make clear suction performance of the very low specific speed centrifugal pump. Recircular flow stopper is installed on the pump casing wall at the region of impeller outlet to improve the pump performance and J-Groove is also installed at the inlet of the pump casing for the purpose of suppressing occurrence of cavitation as well as improving pump performance. The result suggests that the simultaneous improvement of pump performance and suction performance of the very low specific speed centrifugal pump is possible by adopting optimum configuration of the recirculation flow stopper and J-Groove.

• 한국전자파학회논문지
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• 제18권10호
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• pp.1196-1202
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• 2007

본 논문에서는 위성 중계기의 비선형 특성을 포함한 군 지연 및 이득 변동 특성을 감안하여 OFDM 기반 위성통신 시스템에 반송파 간섭 OFDM 및 채널 부호화를 적용하여 성능을 비교함으로써 개선 효과를 분석하였다. 일반적인 OFDM을 적용하는 경우와 반송파 간섭 OFDM을 적용하는 경우를 부가 백색 가우시안 잡음 환경에서 중계기의 특성과 지정된 입력 backoff 상태에 따른 BER 성능을 비교하여 성능 개선 정도를 제시하였다. 36 MHz 대역폭의 중계기 채널에 120 Mps 전송률의 정보를 16 QAM을 사용하여 전송하는 경우에 대하여 중계기의 특성이 이상적인 경우와 최악 조건의 경우로 나누어 모의실험을 적용하였다. 모의실험 결과를 통하여 중계기 내의 성능 열화에 상대적으로 심각한 영향을 미치는 군 지연과 비선형 특성에 대한 반송파 간섭 OFDM과 채널 부호화에 의한 개선 정도가 두드러지게 나타남을 알 수 있었다. 또한, 최악의 조건으로 근접할수록 적용한 채널 부호화에 의한 개선보다 반송파 간섭 OFDM에 의한 개선 효과가 더욱 커짐을 확인할 수 있었다.

• 대한의용생체공학회:의공학회지
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• 제34권1호
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• pp.24-33
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• 2013

To enhance the speech perception of hearing aid users in noisy environment, most hearing aid devices adopt various beamforming algorithms such as the first-order differential microphone (DM1) and the two-stage directional microphone (DM2) algorithms that maintain sounds from the direction of the interlocutor and reduce the ambient sounds from the other directions. However, these conventional algorithms represent poor directionality ability in low frequency area. Therefore, to enhance the speech perception of hearing aid uses in low frequency range, our group had suggested a fractional delay subtraction and integration (FDSI) algorithm and estimated its theoretical performance using computer simulation in previous article. In this study, we performed a KEMAR test in non-reverberant room that compares the performance of DM1, DM2, broadband beamforming (BBF), and proposed FDSI algorithms using several objective indices such as a signal-to-noise ratio (SNR) improvement, a segmental SNR (seg-SNR) improvement, a perceptual evaluation of speech quality (PESQ), and an Itakura-Saito measure (IS). Experimental results showed that the performance of the FDSI algorithm was -3.26-7.16 dB in SNR improvement, -1.94-5.41 dB in segSNR improvement, 1.49-2.79 in PESQ, and 0.79-3.59 in IS, which demonstrated that the FDSI algorithm showed the highest improvement of SNR and segSNR, and the lowest IS. We believe that the proposed FDSI algorithm has a potential as a beamformer for digital hearing aid devices.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2003년도 학술대회지
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• pp.246-249
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• 2003

본 연구에서는 건설공사에서 수행되고 있는 주요 선계변경과 관련하여 설계서와 결함으로 인한 설계변경, 현장상태와 설계서의 상이로 인한 설계변경, 발주자의 필요에 의한 설계변경 등으로 구분하여 설계변경시의 감리업무에 대한 제반규정과 현장에서의 업무수행 현황 등을 비교${\cdot}$분석하는 방법으로 관련규정의 상호모순으로 인한 감리업무 수행의 문제점을 도출하였다. 이를 토대로 설계변경과 관련된 법령/계약조건/지침상의 규정된 내용과 현장에서의 업무수행을 비교${\cdot}$분석하여 공공공시의 설계변경과 관련한 감리업무의 개선방안을 도출하였다.