• Management Science and Financial Engineering
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• 제20권2호
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• pp.27-31
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• 2014

This paper studies the assortment optimization problem in online retailing by using a multinomial logit model in order to take consumer choice behavior into account. We focus on two unique features of online purchase behavior: first, there exists increased amount of uncertainty (e.g., size and color of merchandize) in online shopping as customers cannot experience merchandize directly. This uncertainty is captured by the scale parameter of a Gumbel distribution; second, online shopping entails unique shopping-related disutility (e.g., waiting time for delivery and security concerns) compared to offline shopping. This disutility is controlled by the changes in the observed part of utility function in our model. The impact of changes in uncertainty and disutility on the expected profit does not exhibit obvious structure: the expected profit may increase or decrease depending on the assortment. However, by analyzing the structure of the optimal assortment based on convexity property of the profit function, we show that the cardinality of the optimal assortment decreases and the maximum expected profit increases as uncertainty or disutility decreases. Therefore, our study suggests that it is important for managers of online retailing to reduce uncertainty and disutility involved in online purchase process.

• 한국연초학회지
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• 제17권2호
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• pp.139-148
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• 1995

This study was carried out to investigate the effects of super heated steam on the physical and chemical changes of burley cut tobacco. Total sugar, total alkaloid, ether extracts, crude ash, total nitrogen and pH for leaf chemical constituents were analyzed. Filling power and fineness index for physical properties, and carbonyl compounds, phenol compounds, amonia, pH, hydrogen cyanide nicotine, carbon monoxide, total volatile base and tar for smoke components were also analyzed. The cut tobacco treated with super heated steam showed significant decrease in total sugar and total alkaloid. The filling power of the sample treated with the super heated steam system was increased abruptly when heated at over 250℃. The fineness index showed similar tendency to that of common toast method. Super heated steam treatment slightly decreased carbonyl compounds, phenol compounds, hydrogen cyanide, nicotine, carbon monoxide and tar in the tobacco. Especially the decrease of ammonia was the most remarkable. The pH of smoke was a little different compared with that in the common toast. The sensory test results showed that, compared to the common conveyer moving system, the tobacco treated with super heated steam system brought out more roasted flavor, lowered impact, irritation, and sting, further improved aftertaste, and lowered bitterness. The super heated steam treatment method used in the studies is expected to give better filling power, mild taste and toasted odor of tobacco than that of the common method for toast treatment. Key words : burley tobacco, super heated steam, expansion, toast.

• 한국소음진동공학회논문집
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• 제26권4호
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• pp.375-382
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• 2016

The mechanical property of a carbon-fiber-reinforced plastic (CFRP) is subjected to two elements, carbon fiber and polymer resin, in a first step and the selection of multi-layered structure is second one. Many combination of fabric layers, i.e. plainweave, twillweave, can be derived for candidates of test specimen used for a basic mechanical components so that a reliable identification of dynamic nature of possible multi-layered structures are essential during the development of CFRP based component system. In this paper, three kinds of multi-layered structure specimens were prepared and the dynamic characteristics of service specimens were conducted through classical modal test process with impact hammer. In addition, the design sensitivity analysis based on transmissibility function was applied for the measured response data so that the response sensitivity for each resonance frequency were compared for three CFRP test specimens. Finally, the evaluation of CFRP specimen over different multi-layered fabric structures are commented from the experimental consequences.

• 열처리공학회지
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• 제4권3호
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• pp.39-46
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• 1991

The effects of austenitizing temperatures and times and cooling rate on the characteristics of continuous air cooling have been investigated for 0.3%C-Mn steels microalloyed with vanadium. Transformation start temperatures have been found to be measured from temperature-time curve directly obtained with continuous air cooling and to decrease with increasing austenitizing temperature, cooling rate and Mn contents. The coarsening behavior of austenite grain size has been measured to abnormally grow at $1050^{\circ}C$ and rapidly grow at $1200^{\circ}C$. It has been found that the volume fraction of pearlite was linealy proportional to the reciprocal square root of austenite grain size. The hardness has been measured to increase with increasing cooling rate up to $250^{\circ}C/min.$ and to remain relatively unchanged in the range of $250{\sim}400^{\circ}C/min.$ showing that hardness valves for steel with a higher Mn content increase more than those for steel with a lower Mn content. The impact property has been found to decrease with increasing of austenite grain size but does not linealy change with the reciprocal square root of austenite grain size.

• 한국화재소방학회논문지
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• 제15권2호
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• pp.20-30
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• 2001

The science and technology of seismic hazard mitigation are increasingly being shared among scientists and policy makers around the world. Administrative expertise is also being shared. While there is still tremendous unevenness in technical and administrative capacities and resources, a global community of emergency managers is developing and there is a globalization of expertise. Hazards are better understood, tools for risk assessment are improving, techniques for hazard mitigation are being perfected, and communities and states are implementing more comprehensive disaster preparedness, response, and recovery programs. Priorities are also emerging and hazard mitigation has emerged as the priority of choice in North America and Europe. An increasingly important component of hazard mitigation is resilience, in terms of increased capacities for disaster mitigation and recovery at the community and even individual levels. Each year, more is known about the locations and natures of seismic hazards, although there are still unknown and poorly understood fault lines and limited understanding of related disasters such as tsunamis and landslides. More is known about the impact of earthquakes on the built environment, although nature still provides surprises to confound man's best extorts to reduce risk. More is known about human nature and how people respond to uncertain risk and when confronted by certain catastrophe. However, despite the increased understanding of seismic phenomena and how to protect people and property, there is much that needs to be done to reduce the risk, particularly in major metropolitan areas.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2012년도 춘계학술발표대회
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• pp.100.2-100.2
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• 2012

Surface texturing of crystalline silicon is carried out in alkaline solutions for anisotropic etching that leads to random pyramids of about $10{\mu}m$ in size. Recently textured pyramids size gradually reduced using new solution. In this paper, we investigated that texture pyramids size had an impact on emitter property and front electrode (Ag) contact. To make small (${\sim}3{\mu}m$) and large (${\sim}10{\mu}m$) pyramids size, texturing times control and one side texturing using a silicon nitride film were carried out. Then formation and quality of POCl3-diffused n+ emitter in furnace compare with small and large pyramids by using SEM images, simulation (SILVACO, Athena module) and emitter saturation current density (J0e). After metallization, Ag contact resistance was measured by transfer length method (TLM) pattern. And surface distributions of Ag crystallites were observed by SEM images. Also, performance of cell which is fabricated by screen-printed solar cells is compared by light I-V.

• Journal of Biosystems Engineering
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• 제40권3호
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• pp.159-164
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• 2015

Purpose: Recently, environmental pollution and safety problems in agricultural production have become important issues. Initially, bio-production machines focused on high production efficiency rather than workers' safety and comfort, but this trend slowly has changed as time went on. Methods: This study was carried out to identify sound efficiently and reliably for noise reduction by using a combine cabin model. Ethylene propylene diene monomer (M-class) rubber (EPDM) was applied to improve noise reduction performance from parts connected directly to the front, rear, left side, and bottom side of the cabin. Results: As a result, an average noise reduction of 1.85 dB was achieved in the normal hearing range between 500 Hz to 2 kHz. Conclusions: Reducing the cabin noise levels can reduce a worker's fatigue, improve working environment, and contribute to future low-noise and high-quality cabin environment.

• 한국수학사학회지
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• 제17권4호
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• pp.45-64
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• 2004

${\lambda}$-연산은 ‘다시쓰기 규칙’으로 정의되는 계산을 위해 함수들이 형성되고, 결합되고, 활용되는 수학적 형식 체계이다. 컴퓨터과학의 발전과 더불어 많은 프로그래밍 언어들이 ${\lambda}$-연산을 원리로 삼고 있다. 나아가서, ‘커리-하워드 대응’ 덕분에 미제 연역에 의해 수행된 증명과 컴퓨터 프로그래밍 사이에 대응 관계를 설정할 수 있게 되었다. 이 글의 목적은 교육적인 차원에서 아직은 잘 알려져 있지 않은 주제를 대중화시키는 데에 있다. 논리학과 컴퓨터 과학에서 L-연산의 영향은 차후의 연구과제로 남아 있다.

• Journal of Welding and Joining
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• 제26권4호
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• pp.44-49
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• 2008

Generally, wear plate is steel plate having improved surface contact strength and impact strength by surface hardening which is welded using materials with good corrosion resistance, wear resistance and thermal resistance property. CFP GMAW(Compound Filler Plate Gas Metal Arc Welding) is the cladding method using GMAW with the CFP, which is bound with waterglass, on the substrate. It has advantages of reducing compound powder loss, uniform penetration, and preventing hardness decrease. To develope mass production technique of CFP GMAW process for production of high quality wear plate, the method for controling shallow penetration and increasing productivity is required. In this study, twin torch method applied to CFP GMAW process for increasing productivity. And the method was developed by controling penetration control, CFP dry time, gas formation flux and water glass concentration. As a result, applying twin torch method to CFP GMAW process was possible and high quality wide bead could be made without overlap joint.

• The Journal of Asian Finance, Economics and Business
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• 제7권10호
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• pp.35-42
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• 2020

This study aims to investigate the relationship between the variables of Current Ratio (CR), Return-on-Equity (ROE), Return-on-Assets (ROA), Debt-to-Equity Ratio (DER), and Firm Size (FS) on Dividend Policy (DP) in real estate and property companies listed on the Indonesia Stock Exchange in the period 2016-2019, looking at nine real estate companies in Indonesia. The research methodology uses an explanatory analysis approach and linear regression. Based on the eligibility and homogeneity of the data, the number of sample companies selected was nine companies. The company's financial statement data derived from primary data obtained on the Indonesia Stock Exchange, such as current ratio (CR), return-on-equity (ROE), return-on-assets (ROA), debt-to-equity ratio (DER) and firm size and dividend policy variables. The data analysis procedure is first to transform financial data from the original ratio data into interval data and, then, transform it to ordinal data. Furthermore, the validity and reliability process are ignored because the data is primary. Finally, regression testing is part of the hypothesis testing stage. The results of this study showed that the CR, ROE, and firm size had no positive and significant effect on dividend policy. In contrast, DER and ROA have a positive and significant impact on dividend policy.