• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제9권1호
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• pp.11-16
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• 2020

3D 프린팅은 주목받는 신기술의 하나로 많은 관심을 받고 있다. 3D 프린팅을 하기 위해서는 먼저 3D 모델을 생성한 후, 이를 프린터가 인식할 수 있는 G-code로 변환하여야 한다. 대개 3D 모델은 페이셋이라고 하는 조그만 삼각형으로 면을 표현하는데, 모델의 크기나 정밀도에 따라 페이셋의 개수가 매우 많아져서 변환에 많은 시간이 걸리게 된다. 아파치 하둡은 대용량 데이터의 분산처리를 지원하는 프레임워크로서 그 활용 범위가 넓어지고 있다. 본 논문에서는 3D 모델을 G-code로 변환하는 작업을 효율적으로 수행하기 위해 하둡을 활용하고자 한다. 이를 위해 2단계의 분산 알고리즘을 개발하였다. 이 알고리즘은 여러 페이셋들을 먼저 Z축 값으로 정렬한 후, N등분하여 여러 노드에서 독립적으로 분산처리하도록 되어 있다. 실제 분산처리는 전처리 - 하둡의 Map - Shuffling - Reduce의 4 단계를 거쳐 구현되었다. 최종적으로 성능 평가를 위해 테스트용 3D 모델의 크기와 정밀도에 따른 처리 시간의 효율성을 보였다.

• 정보보호학회논문지
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• 제14권6호
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• pp.69-78
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• 2004

수년간 두 명의 사용자 혹은 세 명의 사용자 사이의 키교환 프로토콜을 위한 안전성 모델이 정의 되어왔다. 또한 최근에는 그룹키 관리 기법에 대한 안전성 모델에 관한 연구가 진행되고 있다. 그 결과 분산 방식의 그룹키 교환 기법을 위한 안전성 모델과 증명 가능한 프로토콜들이 다양하게 제시되고 있다. 그러나 중앙 분배 방식의 그룹키 분배 기법에 대해서는 구체적인 안전성 모델이나 증명 가능한 프로토콜에 대해 거의 언급되지 않았다. 본 논문에서는 중앙 분배 방식의 그룹키 분배 기법을 위한 안전성 요구 조건과 안전성 모델에 대해 설명한다: 이 모델은 강력한 사용자 공모 공격(strong user corruption attack) 능력을 지니고 있는 공격자에 의해 제어되는 채널에서 정의된다. 본 논문에서는 이 안전성 모델에 기반하여 기존의 중앙 분배 방식의 그룹키 기법을 안전성이 증명 가능한 기법으로 전환할 수 있는 변환 모듈을 제시하고자 한다.

• 한국병원경영학회지
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• 제28권3호
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• pp.1-14
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• 2023

Purposes: It is very important to establish a clinical data warehouse based on a common data model to offset the different data characteristics of each medical institution and for drug surveillance. This study attempted to establish a clinical data warehouse for Dankook university hospital for drug surveillance, and to derive the main items necessary for development. Methodology/Approach: This study extracted the electronic medical record data of Dankook university hospital tracked for 9 years from 2013 (2013.01.01. to 2021.12.31) to build a clinical data warehouse. The extracted data was converted into the Observational Medical Outcomes Partnership Common Data Model (Version 5.4). Data term mapping was performed using the electronic medical record data of Dankook university hospital and the standard term mapping guide. To verify the clinical data warehouse, the use of angiotensin receptor blockers and the incidence of liver toxicity were analyzed, and the results were compared with the analysis of hospital raw data. Findings: This study used a total of 670,933 data from electronic medical records for the Dankook university clinical data warehouse. Excluding the number of overlapping cases among the total number of cases, the target data was mapped into standard terms. Diagnosis (100% of total cases), drug (92.1%), and measurement (94.5%) were standardized. For treatment and surgery, the insurance EDI (electronic data interchange) code was used as it is. Extraction, conversion and loading were completed. R language-based conversion and loading software for the process was developed, and clinical data warehouse construction was completed through data verification. Practical Implications: In this study, a clinical data warehouse for Dankook university hospitals based on a common data model supporting drug surveillance research was established and verified. The results of this study provide guidelines for institutions that want to build a clinical data warehouse in the future by deriving key points necessary for building a clinical data warehouse.

• 제어로봇시스템학회논문지
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• 제18권7호
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• pp.638-643
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• 2012

This paper presents an intelligent reduction method for external noise. The main idea comes from PSO-FCM (Particle Swam Optimization Fused fuzzy C-Means) clustering. The data of the target is transformed from the antenna coordinates to the vessel one and to the system coordinates. In the conversion, the overall noises hinder observer to get the exact position and velocity of the maneuvering target. While the filter is used for tracking system, unexpected acceleration becomes the main factor which makes the uncertainty. In this paper, the tracking efficiency is improved with the PSO-FCM and the compensation methodology. The acceleration is approximated from the external noise splitted by the proposed clustering method. After extracting the approximated acceleration, the rest in the noise is filtered by the filter and the compensation is added to after that. Proposed tracking method is applicable to the linear model and nonlinear one together. Also, it can do to the on-line system. Finally, some examples are provided to examine the reliability of the proposed method.

• Journal of the Korean Wood Science and Technology
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• 제40권2호
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• pp.78-90
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• 2012

Soybean hull is an attractive feedstock for glucose production. To increase the glucose conversion in acid hydrolysis, a pretreatment method combined steam explosion with alkali pretreatment for soybean hull was studied. For first step pretreatment, steam explosion conditions (log Ro 2.45) were optimized to obtain maximum solid recovery and cellulose content. In the second step pretreatment, the conditions for potassium hydroxide pretreatment of steam exploded soybean hull were optimized by using RSM (response surface methodology). The optimum conditions for minimum lignin content were determined to be 0.6% potassium hydroxide concentration, $70^{\circ}C$ reaction temperature and 198 min reaction time. The predicted lignin content was 2.2% at the optimum conditions. Experimental verification of the optimum conditions gave the lignin content in similar value with the estimated value of the model. Finally, glucose conversion of pretreated soybean hull using acid hydrolysis resulted in $97.1{\pm}0.4%$. This research of two-step pretreatment was a promising method for increasing the glucose conversion in the cellulose-to-glucose process.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.170-170
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• 2010

The energy conversion from the temperature difference between hot and cold source like ocean thermal energy conversion (OTEC), requires a long and large-diameter pipe (about 1000 to 10,000 meters long) to reach the deep water. The pipe diameter ranges from 2.8 meter for proposed early test systems, to 5 meter for large, commercial power generation systems. The pipe must be designed to resist collapsing pressures produced by water temperature and density differences, and the reduced pressure required to induce flow up the pipe. Other design considerations include the external-drag effect on the pipe due to ocean currents, and the wave-induced motions of the platform to which the pipe is attached. Various approaches to the pipe construction have been proposed, including aluminum, steel, concrete, and fiberglass. More recently, a flexible pipe construction involving the use of fiberglass reinforced plastic has been proposed. This report presents the results of a scaled fixed cold water pipe (CWP) model test program performed by EES(Engineering Equation Solver) to demonstrate the feasibility of this pipe approach.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1346-1349
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• 2004

In this paper, we have proposed the new link-weight calculating function using for routing decision in WDM networks. The proposed link-weight calculating functions includes following factors those are available wavelengths per link, distance loss, total wavelengths, and limited wavelength conversion. The calculated link-weight is applied into the algorithm of routing decision in order to determine the available lightpath that qualifies user requests. The objective is to improve the performance of wavelengths assignment with fast determining the suitable lightpath by using the proposed link-weights calculating function. The analytical model of WDM switching networks is introduced for numerical analysis. The link-weight calculating function is performed. Finally, the performance of proposed algorithm is displayed with numerical results in term of the blocking probability, the probability that connection requests from users are rejected due to there are no available lightpath to be assigned for them. It is also shown that the blocking probability is varied in depending on the number of available wavelengths and the degree of wavelength conversion. The numerical results also show that the proposed link-weight calculating function is more cost-effective choice for the routing decision in WDM switching networks.

• 한국수소및신에너지학회논문집
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• 제25권6호
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• pp.586-593
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• 2014

Limited sources of fossil fuels and also global climate changes caused by $CO_2$ emissions are currently discussed around the world. As a renewable, carbon neutral and widely available energy source, biogas is regarded as a promising alternative to fossil fuels. In this study, a plasma dump reformer was proposed to produce $H_2$-rich synthesis gas by a model biogas. The three-phase gliding arc plasma and dump combustor were combined. Screening studies were carried out with the parameter of a dump injector flow rate, water feeding flow rate, air ratio, biogas component ratio and input power. As the results, methane conversion rate, carbon dioxide conversion rate, hydrogen selectivity, carbon monoxide yield at the optimum conditions were achieved to 98%, 69%, 42%, 24.7%, respectively.

• International Journal of Automotive Technology
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• 제8권6호
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• pp.667-674
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• 2007

Various types of NOx storage catalysts for NGV's were designed, manufactured, and tested in this work on a model gas test bench. As in most of other studies on NOx storage catalyst, alkaline earth metal barium(Ba) was used as the NOx adsorbing substance. The barium-based experimental catalysts were designed to contain different amounts of Ba and precious metals at various ratios. Reaction tests were performed to investigate the NOx storage capacity and the NOx conversion efficiency of the experimental catalysts. From the results, it was found that when Ba loading of a catalyst was increased, the quantity of NOx stored in the catalyst increased in the high temperature range over 350. With more Ba deposition, the NOx conversion efficiency as well as its peak value increased in the high temperature range, but decreased in the low temperature range. The best of de-NOx catalyst tested in this study was catalyst B, which was loaded with 42.8 g/L of Ba in addition to Pt, Pd and Rh in the ratio of 7:7:1. In the low temperature range under $450^{\circ}C$, the NOx conversion efficiencies of the catalysts were lower when $CH_4$, instead of either $C_3H_6$ or $C_3H_8$, was used as the reductant.

• 한국태양에너지학회 논문집
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• 제21권2호
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• pp.1-8
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• 2001

The most effective methods for utilizing solar energy are to use the sunlight and solar thermal energy such as hybrid panel simultaneously and to use concentrator. From such a view point systems using various kinds of photovoltaic panels are constructed in the world. However, there has not been a hybrid panel with a concentrator. If the sunlight is concentrated on solar cell, cell conversion efficiency increases and the temperature of the solar cell s increases. As the temperature of the solar cells increases, the cell conversion efficiency gradually decreases. For maintaining the cell conversion efficiency constant, it is necessary to keep solar cell at low temperature. In this paper, after designing a concentration rate for concentrating, we propose a model for cooling the cell and for using wasted heat. And, we compare it with conventional panels after calculating the electrical and thermal efficiency, using the energy balance equation.