• 산업공학
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• 제16권1호
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• pp.63-69
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• 2003

Virtual Manufacturing is a technology facilitating effective development and agile production of products via computer models representing physical and logical schema and the behavior of the real manufacturing systems including manufacturing resources, environments and products. For the successful application of this technology, a virtual factory as a well-designed and integrated environment is essential. To construct a virtual factory in effective and concurrent manners, a supporting information infrastructure for managing diverse models of virtual factory is very important. In this paper, we constructed the web-based information management system for many engineering activities related with a virtual factory. Using this system, users can handle all information and diverse digital files including attributes, parameters, 3-D CAD files, simulation models, and etc. of a cell, line and whole factory. We expect that this information management system for a virtual factory helps us achieve great time savings and advances in accuracy for construction and maintenance activities of virtual factories.

• 산업공학
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• 제7권3호
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• pp.213-225
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• 1994

For the implementation of CE(Concurrent Engineering), the TDMS(Technical Document Management System) which integrates design and manufacuring information, is required. In this paper a drawing information management system, one of the essential modules for the TDMS has been developed. The system is operated in SUN SPARC II workstations. A CAD software called CIMCAD-2D is used for the storage and management of drawings. Relational DBMS ORACLE is used for the development of information data bases concerned with drawings. As an integration tool, the multi-media software called LINKAGE is used. Various functions for drawings and concerned information have been developed with the internal language CIMSHELL and SQL $^*PLUS$.

• 산업공학
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• 제23권1호
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• pp.58-67
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• 2010

The purpose of this paper is to present the development processes of the assembly line tester of power transmission for lift truck. Because power transmission is most important part of lift truck, all assembled powertrain parts must be inspected for operational defects, pressures and RPM. Developed assembly line tester is designed to take about 25 minutes for inspecting each assembled power transmission and located it at the end of assembled line. The assembly line no-load tester consists of three parts: (1) the driving hardware part; for installing and operating the transmission. (2) control PCB part; send data from sensors to a computer and control driving part, (3) operation software of no-load tester; for an automatic inspection or manual inspection, for database management and printing transcripts.

• 한국전자거래학회:학술대회논문집
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• 한국전자거래학회 1999년도 학술대회지 vol.1
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• pp.215-231
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• 1999

CALS, Enterprise Integration, Virtual Enterprise 등을 구현하는데 있어서 BPR (business process re-engineering), ISP (Information Strategy Planning), Analysis/Design 등은 필수 적이다. 이러한 BPR, ISP, A/D 추진하는데 있어서 각 단계의 산출물은 유연하게 연계되지 못한다. 그 이유는 각 단계가 접근하는 초점이 다르고, 산출물의 성격이 다르며, 무엇보다도 각 단계의 전문가가 다르기 때문에 발생한다. 현재 기업이 각 단계를 추진할 때에는 반복적인 피드백을 통하여 정보를 공유하거나, 각 단계의 정보 연계가 제대로 이루어지지 않는다. 이러한 문제를 해결하기 위하여 BPR-ISP-A/D의 정보 연계를 유연하게 하기 위하여 PPO (Product-Process-Organization) 객체 진화에 의한 통합 방법론을 제안 하고자 한다. 그 과정은 1) Real world 정보를 PPO 객체로 정의하고, 2) PPO 객체를 기반으로 BPR을 수행하여 TO-BE model 을 만드는 동시에, 3) PPO TO-BE model과 함께 IT Architecture를 정의하며, 4) PPO 객체를 기반으로 Analysis and Design 과정을 통하여 Application system 객체 및 Data 객체를 정의한다. 이때 PPO 객체는 Real-world 객체에서 Application system 객체 및 Data 객체로 진화하게 되고 BPR-ISP-A/D의 seamless 통합이 이루어진다. 여기서, 단계 1) 과 2)는 System Engineering을 통하여 이루어진다. ARIS(Architecture of Integrated Information System, Dr. A-W. Scheer, 1998)개념을 도입하여 실세계를 정해진 규약에 따라 Model로 Mapping하고, 생성된 Model을 바탕으로 BPR을 수행하여 개선된 Model을 산출해 낸다. 단계 3)은, IE (Information Engineering, James Martine, 1990) 의 ISP가 도입되어, 설계업무를 지원하기위한 기본적인 시스템 구조를 구상하게 된다. 이와 함께 IT Model을 구성하게 되는데, 객체지향적 접근 방법으로 Model을 생성하고 UML(Unified Modeling Language)을 Tool로 사용한다. 단계 4)는 Software Engineering 관점으로 접근한다. 이는 최종산물이라고 볼 수 있는 설계업무 지원 시스템을 Design하는 과정으로, 시스템에 사용될 데이터를 Design하는 과정과, 데이터를 기반으로 한 기능을 Design하는 과정으로 나눈다. 이를 통해 생성된 Model에 따라 최종적으로 Coding을 통하여 실제 시스템을 구축하게 된다.

• 산업공학
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• 제18권3호
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• pp.234-246
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• 2005

A silicon wafer is a highly customized product made to the individual order varying its electrical and physical characteristics. Therefore, it has distinctive supply chain structure that is different from highly standardized commodity product. For high-volume/high-standardization product, it is general that a main stream of information flow initiated by the production planning of the manufacturers is usually directed to push both ways in a supply chain: upstream to the suppliers and downstream to the customers. Contrastingly, for low-volume/high-customization product, the information flow triggered by the fluctuating customer demand usually propagates upward to the suppliers through the manufacturers. Furthermore, for R &D based hi-technology product like silicon wafer, the interactive information feedback mechanism between manufacturer and customer, which is essential to the new product development process, is to be embedded in the supply chain. This article is a case study of supply chain management system of LG Siltron, a major Korean silicon wafer manufacturer. The SCM system entails special information structure fitting well typical high-variety/high-customization product, and also gives application possibilities to the R&D based high-technology product made to the individual customer order.

• 산업식품공학
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• 제13권4호
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• pp.251-261
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• 2009

In vitro physiological functions such as jack bean (Canavalia ensiformis) urease inhibitory activity and retarding effect of glucose/bile acid of Aloe vera gel concentrated by the optimized DIS (Dewatering Impregnation & Soaking) process conditions were examined. Urease inhibitory activity of DIS aloes ranged from 84.6 to 94.4%, which was similar to or higher than 86.3% of fresh aloe. Also, urease inhibitory activity of DIS aloes was maintained at initial levels after heat treatment (90$^{\circ}C$, 10 min.) and drying treatment (freeze or hot air drying). Urease inhibition pattern from Lineweaver-Burk plot indicated general non-competitive inhibition, and inhibition constants ($K_{IE}$ and $K_{IES}$) of DIS aloes were 41-149 and 87-163 $\mu$L/mL, respectively. DIS(glucose) and DIS(polyethylene glycol) exhibited the highest retarding effect of glucose and bile acid. Their retarding effects were about 1.6 and 1.8 folds higher than that of fresh aloe after 0.5 and 1 hr of the dialysis, respectively. Conclusively, the above in vitro physiological functions of Aloe vera gel concentrated by DIS process suggested that aloe products treated with DIS would have the potential benefits for protection against Helicobacter pylori and reduction of blood glucose and cholesterol levels.

• 대한화학회지
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• 제23권4호
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• pp.198-205
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• 1979

금속이온의 $d^2sp^3$ 혼성궤도함수와 리간드의 singIe basis set 궤도함수를 사용하여 팔면체 [M(II)O_3S_3]$형태 착물의 쌍극자모멘트를 계산하는 원자가결합법을 발전시켰다. [M(III)=V(III), Cr(III), Mn(III), Fe(III), Co(III), Ru(III), Rh(III) 및 Os(III)]. 이 새로운 방법에 있어서 금속이온의 valence basis sets와 리간드 궤도함수사이의 혼성계수가 같다고 가정할 필요가 없으며 이것이 근사분자궤도함수법에 의한 팔면체 전이원소 착물의 쌍극자모멘트를 계산하는 방법과 다른점이다. 원자가결합법에서는 근사분자궤도함수법에서 보다도 훨씬 쉽게 팔면체착물의 쌍극자 모멘트를 계산할 수 있으며 계산한 쌍극자 모멘트의 값이 또한 실험치 범위에든다.

• 전자공학회논문지 IE
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• 제47권3호
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• pp.35-40
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• 2010

본 논문은 MB-OFDM UWB 시스템에서 양자화 잡음의 영향에 의해 저하된 초기 반송파 주파수 오프셋 추정의 정확도를 향상시키는 알고리즘을 제안한다. 일반적인 OFDM 시스템에서 반복적으로 이웃하는 프리엠블 심볼들이 초기 반송파 주파수 동기에 사용되지만, 수신부 A/D 변환기에서 발생한 양자화 잡음의 영향에 의해 주파수 오프셋 추정의 성능은 제한된다. 본 논문에서는 초기 주파수 동기를 위해 이웃하는 한 심볼 간격의 프리엠블 심볼을 사용하는 일반적 방식을 위상 모호성 (phase ambiguity)이 발생하지 않는 범위 안에서 바로 이웃하지 않는 다중 심볼 간격의 프리엠블 심볼에 기반한 방식으로 확장하여 초기 주파수 오프셋 추정의 성능을 향상시키는 다중 심볼 간격 추정 알고리즘이 제안된다. 또한 본 논문은 3-대역 도약 (hopping)하는 최대 30 개의 프리엠블 심볼이 4-비트 A/D 변환기를 통해 입력될 때 최적의 다중 심볼 간격이 '6'임을 구하여 제시한다. MB-OFDM UWB 시스템용 채널 환경에서의 시뮬레이션 결과, 제안된 다중 심볼 간격 추정 방식은 5 ppm 미만의 정확도로 초기 주파수 오프셋을 추정할 수 있음을 확인하였다.

• Corrosion Science and Technology
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• 제21권1호
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• pp.32-40
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• 2022

The o-Vanillin - Glutamine Schiff base [2-Hydroxy-3-Methoxy BenzylidineCarbomyl) -2-Butanoic Acid] was examined for low carbon steel corrosion inhibition in acid media. Weight loss studies were carried out at three different temperatures to determine the inhibition efficiency (IE). Electrochemical impedance spectroscopy revealed that the charge transfer resistance controlled the corrosion reaction and Tafel polarization indicated that the Schiff base acts as mixed mode of inhibitor. SEM images were recorded for the surface morphology of the low carbon steel surface. DFT studies revealed corrosion control mechanisms using quantum chemical parameters such as E_HOMO, E_LUMO, energy gap (∆E), chemical Hardness (η), chemical Softness (σ), Electronegativity (χ), and the fraction of electron transferred (∆N), which is calculated using Gaussian software 09. The gas-phase geometry was fully optimized in the Density Functional Theory (DFT/B3LYP-6-31G (d)).The DFT results are in good agreement with the experimental results. All the results proved that the Schiff Base (2-Hydroxy-3-Metoxy BenzylidineCarbomyl) -2-Butanoic is a suitable alternative for corrosion inhibition of low carbon steel in acid media.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.155-158
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• 2005

An invesitigation on power consumption of a mobile multimedia system using OFDM and MDVS technique is reported here. Analysis and simulation are performed to find the significances of proposed Microscopic Dynamic Voltage Scaling(MDVS) tehnique[4] on digital processor in terms of power saving. A study is also made to show power reduction in mobile multimedia system by incorporating OFDM modulation scheme in RF front-end. Finally, overall power consumption by functionally distinguished blocks ie. RF front-end, digital processor and human interface unit is shown here. Total power consumption is 8.2W for 2Mbps SD-quality WCDMA multimedia video service - the power consumption of digital processor is 3.9W(48%), the power consumption of RF front-end is 3.2W (36%), and the power consumption of interface is 1.8W(16%). Power saving of applying purposed MDVS technique is 35% in digital processor, and power saving of OFDM technique is 10-12dB in RF front-end.