• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.11
• /
• pp.3054-3059
• /
• 2009

Natural black diamonds of single crystal, polycrystalline, and agglomerated roughs become important for their industrial and gem stone application. We performed the conventional gemological tests of thermal diffusion, apparent density, scratch test, and magnification test as well as the advanced tests of Raman spectroscopy, X-ray diffraction test and Lang topography. We conclude that scratch test with SiC paper was the most efficient method in view point of speed and cost. Raman spectroscopy and XRD were useful for identification of diamond while Lang topography offered a good visualization method of the grain structure of polycrystalline black diamond roughs.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.14 no.5
• /
• pp.1059-1068
• /
• 1990

The minimum weight design for the simply-supported eccentrically stiffened plates subjected to combined loads is studied according to the stiffening configuration. The optimal programming is accomplished by formulating the design requirements in terms of a mathematical programming problem, and by using the gradient projection algorithm. The Huber type equilibrium equation is used as the governing equation for the overall buckling. The overall buckling of stiffened plates and the local buckling of the unstiffened plate between stiffeners and the stiffeners themselves are used as behavior constraints. Results of design examples for the orthogonally stiffening case compared with those of the other study support that the present study is feasible. Design examples for the symmetrically oblique stiffening case are presented and the results indicate that a significant improvement in design efficiency may be achieved through symmetrically oblique stiffening compared to the orthogonal stiffening under the combined loading condition.

• The Journal of the Acoustical Society of Korea
• /
• v.31 no.8
• /
• pp.542-550
• /
• 2012

In this paper, an adaptive scheme for network topology configuration is proposed to save the overall energy consumption in underwater acoustic sensor network. The proposed scheme employs a self-organized networking methodology where network topology is locally optimized by exchanging the energy-related information between neighboring nodes such as the remaining energy of each node, in a way that the network life time can be augmented without any centralized control function. Computer simulation is used to evaluate the proposed scheme comparing with LEACH in terms of the number of alive nodes after a given time, the deviation of individual nodes' residual energy and the energy consumption at the initialization and coordination stages.

• Journal of Industrial Convergence
• /
• v.18 no.2
• /
• pp.87-94
• /
• 2020

This paper belongs in a literature of sustainablity policy determination. This paper offers an actual status and explanation to corporate social responsibility of SMEs in Korea. This study examines CSR situation focused on developing mechanisms to enable the SMEs sector. Firstly, this study suggests introducing the third-party professional assurance service on sustainablity reports and/or asking global accreditation such as ISO14001 and ISO26000 when entry as a provider in government e-procurement system. Secondly, this study introduce the CSR Committee headed by the CEO and coordinates group-wide committees to discuss the CSR Guidelines. Third, because CSR does not only have to do with the SMEs, but pertains to the local community and business partner, this study offered the opportunity to work with large companies in aspects of CSR.

• Journal of Korean Association for Spatial Structures
• /
• v.10 no.4
• /
• pp.49-57
• /
• 2010

This study is the research appling the representative Displacement-Based Design which is the basic concept of Direct Displacement Based Design proposed by Chopra and Goel to original Reinforced Concrete structure and determining the thickness of retrofit Steel Jacket about the Maximum design ground acceleration, and developing the more improved Algorithm as well as program by the Retrofit Design method and Nonlinear analysis by the Performance design method before and after reinforcement appling the determined retrofit thickness. To predict the target displacement of retrofitted columns, a nonlinear analysis model of reinforced concrete columns has been developed to be based on the nonlinear fiber cross-sectional and segmental analysis model, and the seismic displacement level of retrofitted columns is estimated by two procedures, the direct displacement-based design method and the displacement coefficient method. In examples of seismic retrofit design, the current seismic improved design method gives good results in improvements of displacement levels and displacement ductilities of retrofitted columns.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2009.05a
• /
• pp.57.1-57.1
• /
• 2009

나노이산화티타늄은 인체에는 화장품, 의약, 식품분야 등에 쓰이고 외부 환경 재료에는 광촉매로서 유독가스 정화제, 옥내 외 항균, 수소발생 가시광 응답형 촉매 및 멤브레인 필터 등과 전자소재용 유전재료, 발광 재료 등 용도가 다양하다. 나노 산화티타늄 화합물의 제조법은 수열합성법, 기상법 등 여러 방법이 있다. 이들에 대한 리뷰의 목적은 2009년도 정부의 투자 계획 중에서 본제목에 관련되는 핵심 산업 재원 원천기술 개발, 태양광, 풍력 등의 신재생 에너지 개발, 록색 기술 개발을 통한 에너지절약형 LED 개발, 차세대 핵심환경 기술 개발, 핵심나노기반기술개발 등의 개발을 위하여 4,363억 원의 예산을 편성하고 연구자와 기술자들이 참여하여 유익한 실적이 창출되기를 원하고 있으므로 본 발표자들은 이 분야에서 연구하는 연구자와 기술자들에게 이 분야에 관련되는 자료를 참고로 제시하는데 있다. 페로브스카이트형 산화물인 유전재료($BaTiO_3$), 발광재료(CaTiO3:Pr3+적색), 박막형 반응기재료($Ca0.8Sr0.2TiO_3$), 등의 여러 가지 산화물은 류통식 급속 승온 수열 합성법, 겔 졸 법, 수열 합성법 등 여러 방법에 의하여 페로브스카이트형 산화물 입자 직경이 약 20nm~100nm 범위까지 합성된다. 태양광을 조사하여 물을분해 해서 수소를 생산하는 산화티타늄계 가시광 응답형 Vis-$TiO_2$ 박막은 기상법으로 제조하는데 한 예로써 RF 스퍼터링법으로 박막을 제조하여 수소와 산소를 회수하였으며, 황도프산화티타늄, 질소 도프 산화티타늄은 유기물 분해에 의한 공해제거, $NO_x$ 제거 등 환경정화에 사용되고, 고온 고압수법/산화티타늄 복합기술에 의해서는 바이오매스 분해 하고, 일종의 수열법인 개량형 HyCOM 법은 가시광 응답성 산화티타늄을 합성하여 NO가스 제거에 사용한다. 이들 여러 방법에 관한 것을 소개하고저 한다.

• Journal of agriculture & life science
• /
• v.44 no.1
• /
• pp.69-80
• /
• 2010

The purpose of this study is to analyse current marketing practices and marketing efficiency using operational efficiency. Through field survey on marketing situations and channels, we found that major marketing channels of paprika were classified into six types : channels in exporting market included (1) producer's organization leading channel (type I), (2) regional cooperative leading channel (type II), (3) individual producer leading channel (type III), and channels in domestic market included (4) wholesale markets targeting channel (type IV), (5) distribution agents targeting channel (type V), (6) cooperative system selling channel (type VI). According to the estimated result of operational efficiency of marketing channels, marketing efficiency of type III and IV was relatively higher than type I,II and type V, VI respectively.

• Korean Chemical Engineering Research
• /
• v.57 no.3
• /
• pp.438-443
• /
• 2019

A new measurement method is suggested to quantify the phosphate poisoning of cathodic Pt catalyst for HT-PEMFC. To do that, hydrogen peroxide was used as an indicator to reduce the error which has been occurred in conventional electrochemical measurement such as CV or ORR RDE with high concentration of phosphate ions. As a result, the current density induced from the reaction of hydrogen peroxide decomposition increased proportionally to the concentration of phosphate ion while the conventional methods show has a significant error with high concentration of phosphate ion. Thus, it is confirmed that the suggested way is superior to the conventional measurement method for the quantification of phosphate ion poisoning in an atmosphere similar to the actual operation condition of HT-PEMFC.

• Journal of Digital Convergence
• /
• v.20 no.2
• /
• pp.269-275
• /
• 2022

As artificial intelligence services targeting humans increase, social demands are increasing that artificial intelligence should also be made on an ethical basis. Following this trend, the government and businesses are preparing policies and norms related to artificial intelligence ethics. In order to establish reasonable policies and norms, the first step is to understand the public's perceptions. In this paper, social data and news comments were collected and analyzed to understand the public's perception related to artificial intelligence and ethics. Interest analysis, emotional analysis, and discourse analysis were performed and visualized on the collected datasets. As a result of the analysis, interest in "artificial intelligence ethics" and "artificial intelligence" favorability showed an inversely proportional correlation. As a result of discourse analysis, the biggest issue was "personal information leakage," and it also showed a discourse on contamination and deflection of learning data and whether computer-made artificial intelligence should be given a legal personality. This study can be used as data to grasp the public's perception when preparing artificial intelligence ethical norms and policies.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2023.05a
• /
• pp.198-198
• /
• 2023

유역 내 수자원 계획을 효율적으로 수립하기 위해서는 장기간에 걸친 수문 모델링 뿐만 아니라 미래 기후 시나리오에 따른 수문학적 기후변화 영향 분석도 중요하다. 이를 위해서는 관측 값에 기반한 고품질 및 고해상도 격자형 기상자료 생산이 필수적이다. 하지만, 우리나라는 종관기상관측시스템(ASOS)과 방재기상관측시스템(AWS)으로 이루어진 고밀도 관측 네트워크가 2000년 이후부터 이용 가능했기에 장기간 격자형 기상자료가 부족하다. 이를 보완하고자 본 연구는 가정적인 상황에 기반하여 만약 2000년 이전에도 현재와 동일한 고밀도 관측 네트워크가 존재했다면 산출 가능했을 장기간 일 단위 고해상도 격자형 기상자료를 생산하는 것을 목표로 한다. 구체적으로, 2000년을 기준으로 최근과 과거 기간의 격자형 기상자료를 딥러닝 알고리즘으로 모델링하여 과거 기간을 대상으로 기상자료(일 단위 기온, 강수량)의 공간적 변동성 및 특성을 재구성한다. 격자형 기상자료의 생산을 위해 우리나라의 고도에 기반하여 기상 인자들의 영향을 정량화 하는 보간법인 K-PRISM을 적용하여 고밀도 및 저밀도 관측 네트워크로 두 가지 격자형 기상자료를 생산한다. 생산한 격자형 기상자료 중 저밀도 관측 네트워크의 자료를 입력 자료로, 고밀도 관측 네트워크의 자료를 출력 자료로 선정하여 각 격자점에 대해 Long-Short Term Memory(LSTM) 알고리즘을 개발한다. 이 때, 멀티 그래픽 처리장치(GPU)에 기반한 병렬 처리를 통해 비용 효율적인 계산이 가능하도록 한다. 최종적으로 1973년부터 1999년까지의 저밀도 관측 네트워크의 격자형 기상자료를 입력 자료로 하여 해당 기간에 대한 고밀도 관측 네트워크의 격자형 기상자료를 생산한다. 개발된 대부분의 예측 모델 결과가 0.9 이상의 NSE 값을 나타낸다. 따라서, 본 연구에서 개발된 모델은 고품질의 장기간 기상자료를 효율적으로 정확도 높게 산출하며, 이는 향후 장기간 기후 추세 및 변동 분석에 중요 자료로 활용 가능하다.