• Journal of Advanced Marine Engineering and Technology
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• 제39권5호
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• pp.522-526
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• 2015

Generally, underwater unmanned vehicle have adopted an inertial navigation system (INS), dead reckoning (DR), acoustic navigation and geophysical navigation techniques as the navigation method because GPS does not work in deep underwater environment. Even if the tactical inertial sensor can provide very detail measurement during long operation time, it is not suitable to use the tactical inertial sensor for small size and low cost UUV because the tactical inertial sensor is expensive and large. One alternative to INS is attitude heading reference system (AHRS) with the micro-machined electro mechanical system (MEMS) inertial sensor because of MEMS inertial sensor's small size and low power requirement. A cost effective and small size attitude heading reference system (AHRS) which incorporates measurements from 3-axis micro-machined electro mechanical system (MEMS) gyroscopes, accelerometers, and 3-axis magnetometers has been developed to provide a complete attitude solution for UUV. The AHRS based MEMS overcome many problems that have inhibited the adoption of inertial system for small UUV such as cost, size and power consumption. Several evaluation experiments were carried out for the validation of the developed AHRS's function and these experiments results are presented. Experiments results prove the fact that the developed MEMS AHRS satisfied the required specification.

• 보건행정학회지
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• 제3권1호
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• pp.84-101
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• 1993

The current method of rate adjustment is based on the evaluation of the financial performance of hospitals. The method has the disadvantages such as too complicated, expensive process as well as low reliability due to small sample size. This study, therefore, develops a new model for the rate adjustment with the use of the composite index. In addition to that, it examines the validity of the model by comparing the result of the new method with that of the conventional method. The idea of the new model comes from the Medicare Economic Index(MEI) on which physician fees for the Medicare patients are adjusted periodically in the United States. Medical costs are classified into three groups : labor costs, materials and other expenses. Labor costs are subdivided into physicians and other personnels. Materials are subdivided into drugs and others. Other expenses are subdivided into 5 items. Macro economic indices are selected for each cost item in order to reflect the cost inflation during the specific period. Then the composite index which integrate all items according to the ration of each item in the total costs is calculated. The result from the application of empirical data to the new model is very similar to that of the current method. Furthermore, this method is very simple and also to easy to get social concensus. This model can be replaced the current method based on the analysis of the financial performance for the adjustment of medical fees.

• 한국인터넷방송통신학회논문지
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• 제21권3호
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• pp.73-79
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• 2021

4차 산업 혁명의 물결 속에서 스마트팩토리는 많은 공장에서 요구되고 있다. 하지만, 중소/중견 기업에서는 여전히 노후화된 설비를 보유하고 있어 스마트팩토리의 기초가 되는 데이터 수집 단계에서 어려움을 겪고 있다. 이 연구는 기존 설비의 개조 필요 없이, 설비 제어판의 이미지로부터 데이터를 추출하는 오픈 소스 기반의 기술을 활용 함으로써, 저비용으로 설비 모니터링하는 방법을 제안한다. 제안된 방법은 프로토타핑을 통해 자동차 부품 제조 공장의 단조 설비를 대상으로 테스트하고 평가되었다. 평가 결과 저가형 설비 모니터링이 가능함을 확인하였으며, 중소/중견 기업이 스마트팩토리를 구축하는 데 도움을 줄 것이다.

• 대한인간공학회지
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• 제30권6호
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• pp.765-773
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• 2011

Objective: This study aims towards exploring a model of the HCI evaluation methods to improve the usability of mobile device, based on a case of a Mobile PDA system in a Museum context. Background: Mobile PDA systems in a Museum context is widely utilized for the educational purposes, but it is criticized for low usability that the device only play a role in textbooks on legs without any interactive educational activities. Therefore, the usability improvements on the mobile PDA system should be considered. Method 1: This model was developed with a combination of the expert review and the user testing, and with a combination of the qualitative and quantitative studies. In more details, first of all, a qualitative study was conducted as a combination of three different methods: 1) expert review with heuristics, 2) interviews with persons working in a museum, and 3) contextual enquiry. Results 1: The experts review provided with critical usability issues, and the semi-constructive interview helped to understand the background of the mobile device. Lastly, the contextual enquiry showed user experience problems and directions of improving the device from user's perspective. Method 2: Based on the results of the qualitative study, a questionnaire was designed. Results 2: The analysis of the quantitative study was conducted to generalize the problems, and prioritize the direction of improving the device within the limitation of the cost and time in a museum. Conclusion: This study has implications in developing an example of a HCI evaluation model to improve the user experience of the mobile device as well as finding problems and directions of how to improve the mobile PDA systems in the museum. Application: In fact, most of the studies related to the evaluation of the mobile device have been conducted in a laboratory context due to the cost and time. This paper, however, attempted to apply to various HCI research techniques from different constituents in real context.

• 대한토목학회논문집
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• 제29권5D호
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• pp.627-634
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• 2009

최근 국내에서 많이 시행되고 있는 BTL(Build Transfer Lease)사업은 수익성이 낮은 문화, 교육, 복지부문의 사회기반시설을 조기에 확충함으로써 국민들의 삶의 질을 높여주는 역할을 한다. 그러나 현재까지 BTL사업의 공사비는 초기공사비에 중점을 두고 있으며, 상대적으로 운영비 산정에 대한 합리적 기준이 정해져 있지 않아 비효율적인 낮은 운영비 관리체계가 되고 있다. 저가 운영비는 사업완공 후 시설 운영시 서비스의 질을 저하할 수 있고, 사업의 성과에도 큰 영향을 미친다. 따라서 본 연구에서는 기존 하수처리시설의 운영부문에 대한 실적자료를 이용하여 사업계획 초기에 운영비와 운영인력을 산정하는 방안을 제시한다. 이러한 연구는 향후 BTL사업으로 시행되는 하수처리시설의 계획시 시설 규모에 따른 개략적인 운영비 산정에 활용성을 갖을 것으로 기대되며, 타 시설물의 BTL사업 운영비 산정체계 구축시 참고 자료가 될 수 있다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.768-773
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• 2003

The inspection of track irregularity, which is the most important index for the evaluation of the dynamic safety of the rolling stock, is performed by setting up the testing train set. The self-diagnosis for the various rolling stocks and railways can be obtained if it is possible to take the simultaneous inspection of track irregularity for the commercial vehicle while it is running and to build up a dynamic safety evaluation system. It is expected to have some good effects, such as preventing accident with the low dynamic safety, cutting cost for the testing train set and evaluating the exact influence on the rolling stock and railway. In this study, innertial measuring method, which allows us to directly measure the track irregularity from the commercial vehicle, will be considered and some overseas cases will be explored as well.

• Imaging Science in Dentistry
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• 제47권2호
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• pp.75-86
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• 2017

Purpose: The purpose of this study was to apply a newly developed free software program, at low cost and with minimal time, to evaluate the quality of dental and maxillofacial cone-beam computed tomography (CBCT) images. Materials and Methods: A polymethyl methacrylate (PMMA) phantom, CQP-IFBA, was scanned in 3 CBCT units with 7 protocols. A macro program was developed, using the free software ImageJ, to automatically evaluate the image quality parameters. The image quality evaluation was based on 8 parameters: uniformity, the signal-to-noise ratio (SNR), noise, the contrast-to-noise ratio (CNR), spatial resolution, the artifact index, geometric accuracy, and low-contrast resolution. Results: The image uniformity and noise depended on the protocol that was applied. Regarding the CNR, high-density structures were more sensitive to the effect of scanning parameters. There were no significant differences between SNR and CNR in centered and peripheral objects. The geometric accuracy assessment showed that all the distance measurements were lower than the real values. Low-contrast resolution was influenced by the scanning parameters, and the 1-mm rod present in the phantom was not depicted in any of the 3 CBCT units. Smaller voxel sizes presented higher spatial resolution. There were no significant differences among the protocols regarding artifact presence. Conclusion: This software package provided a fast, low-cost, and feasible method for the evaluation of image quality parameters in CBCT.

• 한국습지학회지
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• 제19권3호
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• pp.359-365
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• 2017

도로 및 주차장과 같은 불투수면은 건기시 중금속과 입자상 물질을 축적하여 강우시 하천 수질을 악화시키는 원인으로 작용하며, 도시의 물순환 체계를 왜곡시킨다. 이에 정부는 최근 인도와 주차장의 불투수면을 투수가 가능한 LID 시설 중 하나인 투수 및 잔디 블록으로 대체하는 정책을 추진 중에 있다. 그러나 불투수면을 투수 및 저류가 가능한 잔디 블록으로 대체할 때 발생하는 건설폐기물은 환경을 오염시킬 뿐만 아니라 공사비용을 증가시킨다. 따라서 본 연구는 건설폐기물을 최소화 할 수 있는 비용 효율적인 주차장 시공방법을 제안하기 위해 수행되었다. 본 연구는 Lab-scale 실험을 통해 기존의 시공방법과 본 연구에서 제안하는 방법에 대한 물순환 능력 및 경제성 등의 비교분석을 수행하였다. 본 연구에서 제안하는 시공방법은 기존 아스팔트 천공, 투수기층재 및 부설층 포설 및 다짐, 노상다짐, 블록 포설, 틈새재 포설 및 다짐의 순이며, Lab-scale 실험 결과 기존 방법과 제안 기법에서 표면유출량, 침투량, 저류량 및 강우유출 지체시간은 큰 차이가 없는 것으로 분석되었다. 반면 폐기물 발생량 및 경제성 평가에서는 본 제안기법이 기존 시공법보다 약 86% 건설폐기물이 적게 발생하며, 이에 따른 비용이 약 70% 절감되는 것으로 나타났다. 본 연구에서 제안하는 시공 방법이 기존 방법과 물순환 효과는 비슷하지만, 시공절차가 용이하고 경제성이 높은 것으로 평가되었다.

• Nuclear Engineering and Technology
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• 제51권3호
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• pp.807-817
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• 2019

Airborne Gamma Ray Spectrometry (AGRS) with its important applications such as gathering radiation information of ground surface, geochemistry measuring of the abundance of Potassium, Thorium and Uranium in outer earth layer, environmental and nuclear site surveillance has a key role in the field of nuclear science and human life. The Broyden-Fletcher-Goldfarb-Shanno (BFGS), with its advanced numerical unconstrained nonlinear optimization in collaboration with Artificial Neural Networks (ANNs) provides a noteworthy opportunity for modern AGRS. In this study a new AGRS system empowered by ANN-BFGS has been proposed and evaluated on available empirical AGRS data. To that effect different architectures of adaptive ANN-BFGS were implemented for a sort of published experimental AGRS outputs. The selected approach among of various training methods, with its low iteration cost and nondiagonal scaling allocation is a new powerful algorithm for AGRS data due to its inherent stochastic properties. Experiments were performed by different architectures and trainings, the selected scheme achieved the smallest number of epochs, the minimum Mean Square Error (MSE) and the maximum performance in compare with different types of optimization strategies and algorithms. The proposed method is capable to be implemented on a cost effective and minimum electronic equipment to present its real-time process, which will let it to be used on board a light Unmanned Aerial Vehicle (UAV). The advanced adaptation properties and models of neural network, the training of stochastic process and its implementation on DSP outstands an affordable, reliable and low cost AGRS design. The main outcome of the study shows this method increases the quality of curvature information of AGRS data while cost of the algorithm is reduced in each iteration so the proposed ANN-BFGS is a trustworthy appropriate model for Gamma-ray data reconstruction and analysis based on advanced novel artificial intelligence systems.

• Journal of Welding and Joining
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• 제19권4호
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• pp.379-383
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• 2001

Resistance spot welding has been widely used in the sheet metal joining processes because of low cost, high productivity and convenience. Recently, automobile and aerospace industries are trying to replace partly steel sheets with aluminum alloy sheets. But in the case of dissimilar materials, to apply resistance spot welding has been known to be very difficult owing to the effect of melting temperature. On this study, an effort was made to apply spot welding of dissimilar sheet metals, 2024 aluminum alloy and zinc coated steel sheet, evaluate the spot weld quality with tensile-shear strength test and nondestructive evaluation technique, C-scan image methodology. In this study results, as the current below 11 kA, melting of materials is not achieved well. Also as the current exceeds to 13.5 kA, the more spatters happen at welded zone and tensile-shear strength lowered. So, the feasibility of C-scan image technique proposed in the study is found to be suitable evaluation method for resistance spot weldability.