• 공업화학
• /
• 제8권3호
• /
• pp.416-424
• /
• 1997

본 연구에서는 고밀집 섬유체에 의한 정적 액-액 접촉기에 대한 이론적 모델링을 통하여 섬유체 접촉기 내부에서의 물질 이동과정과 각 상에서의 축 방향 농도분포 해석이 수행되었고, 여러 운전 조건하에서 출구 농도를 예측하여 실험치와 비교하였다. 본 섬유체 액-액 추출기는 그 구조적 특성 때문에 축 방향 분산이 없는 플러그 흐름 모델로 완벽하게 묘사될 수 있었으며 data fitting을 통해 결정되어 모델식에 적용된 물질전달 계수와 섬유체 추출기 축 방향 반위 길이 당 물질전달 면적의 곱의 항인 $k_a{\sigma}$은 그 섬유체 추출기의 고유 특성 값으로 사용될 수 있었고, 그 값은 약 0.0327cm2/sec이었다.

• Human Ecology Research
• /
• 제52권6호
• /
• pp.601-616
• /
• 2014

This study's aim was to explore the relationships among consumers' perceived risk, trust, and familiarity with products made in China. We invited 489 Korean adult consumers, who had purchased products made in China earlier, to take part in this investigation. Data analyses were conducted using a reliability test, confirmatory factor analysis, and structural equation modeling (SEM) with SPSS ver. 21.0 and AMOS ver. 21.0. We assumed that the perceived risk could be classified into four types: financial, performance, psychological, and social risk. The empirical verification through SEM indicated that all four types of the perceived risk represented a negative influence on the trust. Further, only the financial and psychological risks were significant when consumers were not familiar with products made in China (novice); in contrast, the experts (consumers familiar with products made in China) showed that the performance and social risks were effective. Finally, we found that there was a moderating effect of familiarity on the relationship between three types of perceived risk, namely financial, performance, and psychological risks, and trust, but the social risk was not affected. The results of this research should help us to understand the consumers' risk perception of imported goods and to formulate criteria on the basis of which the consumers evaluate these products. This research can help companies, particularly those in China, to formulate market strategies effectively when they enter a foreign market such as Korea by exploring the influence of the perceived risk on local consumers' purchasing behaviors as well.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2003년도 춘계학술대회 논문집
• /
• pp.1643-1646
• /
• 2003

Drawing is a mechanical operation that attenuates thick material to an appropriate thickness for the next processing or end usage. When the input material has the form of a bundle or bundles made of very thin and long shaped wire or fibers, this attenuation operation is called "bundle drawing" or "drafting" Drafting is being used widely in manufacturing staple yarns. which is indispensable for the textile industry. However, the bundle processed by this operation undertake more or less defects in the evenness of linear density. Such irregularities cause many problems not only for the product quality but also for the efficiency of the next successive processes. Since long there have been many researches tying to find out factors affecting the irregularity of linear desity, to obtain optimal drafting conditions, to develop efficient measuring and analysis methods of linear density of bundle, etc., but there exists yet no fundamental equation describing the dynamic behavior of the flowing bundle during processing. In this research a mathematical model for the dynamic behavior of the bundle fluid is to be set up on the basis of general physical lows representing physical variables, i.e. linear density and velocity as the dynamic state of bundle. The conservation of mass and momentum balance was applied to the fluid field of bundle. while the movement of′ individual material was taken into account. The constitutive model relating the surface force and the deformation of bundle was introduced by considering a representative prodedure that stands for the bundle movement. Then a fundamental equations system could be simplified considering a steady state of the process. On the basis of the simplified model, the simulation was performed and the results could be confirmed by the experiments under various conditions.

• 산업경영시스템학회지
• /
• 제39권2호
• /
• pp.150-160
• /
• 2016

The quality of service in ERP services is a key issue in innovating the ERP performance as an IT service for corporations. Currently, most of the research works for this area are based on the existing quality models such as SERVQUAL, which are said not to measure service quality properly. Also, it does not consider the factor of the system acceptance, which is thought to be closely related to the quality of service in this type of IT services. Therefore, a research model is required, which can address the issues related to the ERP service quality measurements. In this paper, new research models have been proposed, and empirical data obtained from SME's ERP users have been applied to the proposed model to analyze the causal relationship between quality factors and to identify the most suitable quality measures. Also, the relationship between the service quality and the system acceptance was analyzed using a combined model. The results show that factors such as productivity and convenience affects the quality mostly and that the most appropriate measure for the service quality of ERP service is satisfaction. Also, for the system acceptance, the ease-of-use is the main factor. And, the service quality and system acceptance shows a strong correlation. This means that, in order to enhance the quality of ERP services, the service provider needs to provide customers with productivity-enhanced user-friendly IT services and active product support. The work of this research can help to improve the service quality and the user acceptance of ERP services and to lead further research works in this area.

• 터널과지하공간
• /
• 제27권2호
• /
• pp.69-76
• /
• 2017

지하광산 물리모형은 그 시각적인 효과로 인해 광산 개발 및 컨설팅 과정에서 광산공동 설계 또는 공정관리 등의 효율성을 제고하는 데 매우 유용하다. 다양한 기업에서 갱내를 3차원 영상으로 구현하는 기술이 개발된 바 있지만, 현재까지도 갱도 전체를 가시적으로 파악하기 쉬운 물리모형이 널리 이용되고 있다. 기존의 물리모형 제작 방법은 종이나 아크릴 등의 재료를 이용하여 수작업으로 모형을 제작하므로 정밀도가 떨어지고 소요시간 및 비용이 매우 큰 단점이 있다. 따라서, 이 연구에서는 최근 각 분야에서 널리 활용되고 있는 3D프린팅 기술을 적용하여 지하광산 갱도의 물리모형을 저비용으로 정밀하고 신속하게 제작하는 기법을 개발하였으며, 최종적으로, 소프트웨어 "UMine2STL"을 개발하고 광산 갱도 일부를 출력하여 그 활용성을 검증하였다.

• 벤처창업연구
• /
• 제10권6호
• /
• pp.107-119
• /
• 2015

최근 부유층 주거지에 특정 목적에 의한 중 저소득층이 진입, 준거집단에 합류하며 과시효과를 누리고 싶어 한다. 이 현상으로 주거용부동산에 대해 유한계급층이 아닌 일반 소비자들의 과시효과에 대한 욕구를 유추할 수 있다. 과시소비를 함으로써 고가의 상품을 구매할 수 있는 준거집단에 속한다는 우월함과 고가를 지불할 수 있는 능력을 통해 부를 전시하는 효과를 얻는다고 볼 때 자신의 사회경제적 능력을 보이기 위한 과시적 소비성향은 주거용부동산에도 영향을 미치리라고 예상된다. 본 연구에서는 주거부동산의 거주유형에 따른 베블런효과를 확인하고자 하였다. 이를 위해 다양한 심리적 특성, 주거특성, 인구사회학적 특성이 베블런효과에 미치는 영향을 PLS 경로모형을 이용하여 분석하였다. 분석결과 차가거주자가 자가거주자에 비해 과시소비성향이 높은 것으로 나타났으며, 체면민감성은 자아존중감과 주거유형에 정(+)의 영향을 미치며 이는 과시소비성향으로 이어진다. 또한 거주면적이 크고 소득수준이 높을수록 과시소비성향이 큰 것으로 확인되었다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2002년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.197-199
• /
• 2002

The invention of VHDL(Very High Speed Integrated Circuit Hardware Description Language), Technical language of Hardware, is a kind of turning point in digital circuit designing, which is being more and more complicated and integrated. Because of its excellency in expression ability of hardware, VHDL is not only used in designing Hardware but also in simulation for verification, and in exchange and conservation, composition of the data of designs, and in many other ways. Especially, It is very important that VHDL is a Technical language of Hardware standardized by IEEE, intenational body with an authority. The biggest problem in modern circuit designing can be pointed out in two way. One is a problem how to process the rapidly being complicated circuit complexity. The other is minimizing the period of designing and manufacturing to survive in a cutthroat competition. To promote the use of VHDL, more than a simple use of simulation by VHDL, it is requested to use VHDL in composing logical circuit with chip manufacturing. And, by developing the quality of designing technique, it can contribute for development in domestic industry related to ASIC designing. In this paper in designing SMPS(Switching mode power supply), programming PWM by VHDL, it can print static voltage by the variable load, connect computer to chip with byteblaster, and download in Max(EPM7064SLCS4 - 5)chip of ALTER. To achieve this, it is supposed to use VHDL in modeling, simulating, compositing logic and product of the FPGA chip. Despite its limit in size and operating speed caused by the specific property of FPGA chip, it can be said that this method should be introduced more aggressively because of its prompt realization after designing.

• Tribology and Lubricants
• /
• 제32권4호
• /
• pp.113-118
• /
• 2016

As an economic, high quality, and highly reliable gear with low noise and low vibration is demanded, an overall finite element analysis regarding a gear is required. Also, an infrared thermography test, which is a quantitative testing technique, is demanded for safety and longer lifespan of gear products. In order to manufacture a gear product or to determine safety of a gear being used, it is necessary to precisely determine ingredients of a material constituting a gear and detect any internal defect. This study aims to realize a design that minimizes the spur gear displacement with respect to power during its rotation and ensures the spur gear control capacity by using a 3D model and the midasNFX program. This facilitates the assessment of the possibility of cracking by evaluating the stress intensity and focusing on the integrity of the spur gear. We prepare the specimen of the spur gear based on the possibility of cranking as per the result of the structural interpretation from an infrared ray thermal measuring technique. After cooling the spur gear, we perform experiments using thermography and halogen lamps and analyze the temperature data according to the results of the experiment. In the experiment which we use thermography after cooling, we find a rise in the temperature of the room. As a result, the defective part show temperatures lower than their surroundings while the normal parts have temperatures higher than the defective parts. Therefore, it possible to precisely identify defective part owing to its low temperature.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2006년도 춘계학술대회 논문집
• /
• pp.321-322
• /
• 2006

In many manufacturing processes such as web formation, manufacturing of paper and nonwoven, fabric weaving, etc., planar sheets are transported and at the same time appropriate tension is imposed. The input material rolled up on beams is fed by unwinding the beam and the processed is then taken up on beams by winding it. While processed, the planar sheets are thrown under the processing load of impulse form, which causes irregular thickness of the processed sheet. To improve the quality of the product, a dynamic model is needed and the dynamic characteristics is to be analyzed by simulation. This study shows that density variation dynamics of the in-process-sheet in the machine direction can be described at each moment of disturbing impacts in forms of difference equations, while the impacts and tension, the time-dependency of the material properties were taken into account. Simulation showed the most serious variation of the density occurred in the process starting phase. The starting velocity curve with step form showed the least variation of the density. As the time order of the function of the starting velocity cure becomes higher, the density variation gets greater.

• 공업화학
• /
• 제7권3호
• /
• pp.443-452
• /
• 1996

석유화학공정에서 fouling현상은 열교환기, 보일러, desalter 등 주요 전처리 시설 및 공정에 polymer, heavy paraffine, chemicals, heavy organics, asphaltene, resin, metallics, salts 등 불순물들이 침적 및 부식을 일으켜 각종 조업에 있어서 에너지의 다량소비 및 product yield의 감소 또는 공정의 중단으로 말미암아 생산성의 손실이 대단히 크다고 볼 수 있다. 본 연구에서는 석유화학 공정에서 foulants의 분리되는 양을 계산하고, 제어할 수 있는 model의 개발을 위하여 fouling 현상에 대한 modeling을 연속열역학과 Peng-Robinson 상태 방정식, 고분자 용액 이론, 다성분계 열역학 이론 등을 이용하여 fouling 현상에 대한 메카니즘규명과 모델링을 하였다.