• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.565-568
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• 2014

This paper presents a 0.2V DC/DC boost converter with regulated output for thermoelectric energy harvesting. To use low voltages from a thermoelectric device, a start-up circuit consisting of native NMOS transistors and resistors boosts an internal VDD, and the boosted VDD is used to operate the internal control block. When the VDD reaches a predefined value, a detector circuit makes the start-up block turn off to minimize current consumption. The final boosted VSTO is achieved by alternately operating the sub-boost converter for VDD and the main boost converter for VSTO according to the comparator outputs. When the VSTO reaches 2.4V, a buck converter starts to operate to generate a stabilized output VOUT. Simulation results shows that the designed converter generates a regulated 1.8V output from an input voltage of 0.2V, and its maximum power efficiency is 60%. The chip designed using a $0.35{\mu}m$ CMOS process occupies $1.1mm{\times}1.0mm$ including pads.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.4
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• pp.179-186
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• 2019

In this study, we investigated the structural properties of $Ga_2O_3$ thin films and the photo-electrical properties of metal-semiconductor-metal (MSM) photodetectors deposited by Ti/Au electrodes. $Ga_2O_3$ thin films were grown at different temperatures using metal organic chemical vapor deposition (MOCVD). The crystal phase of $Ga_2O_3$ changed from ${\varepsilon}$-phase to ${\beta}$-phase depending on the growth temperature. The crystal structure of ${\varepsilon}-Ga_2O_3$ was confirmed by X-ray diffraction (XRD) analysis and the formation mechanism of crystal structure was discussed by scanning electron microscopy (SEM) images. From the results of current-voltage (I-V) and time-dependent photoresponse characteristics under the illumination of external lights, we confirmed that the MSM photodetector fabricated by ${\varepsilon}-Ga_2O_3$ showed much better photocurrent characteristics in the 266 nm UV range than in the visible range.

• Journal of the Korea Institute of Building Construction
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• v.19 no.3
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• pp.263-272
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• 2019

Building Information Modeling (BIM) and modular construction are regarded as important technologies that have contributed to advancements in the construction industry. However, the utilization of BIM in current modular construction projects is limited; moreover, there are no specific guidelines pertaining the applications of BIM in modular construction projects. Therefore, this study aims to analyze the utilization of BIM for onsite construction planning in modular construction projects. First, a realistic BIM application was selected through literature review and expert interviews. Then, the construction plan of the modular projects was analyzed to classify the BIM application items into five different categories. The utilization of BIM in each category was then analyzed in terms of necessity and efficiency using a questionnaire. Finally, the BIM Utilization Index (BIM UI) was suggested based on the findings of the survey. As a results, the BIM UI for module point details, lifting plan, other installation details, site layout plan, and schedule plan was 0.811, 0.787, 0.770, 0.729, and 0.699, in the descending order of usability. In addition, through the findings of the study and interviews with experts, a case study for implementation of BIM in modular construction plan was conducted. The results of this study can be used as application guidelines for BIM in future modular construction projects.

• Applied Chemistry for Engineering
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• v.22 no.5
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• pp.551-554
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• 2011

One of the key issues in the research of organic field-effect transistors (OFETs) is the low-voltage operation. To address this issue, we synthesized poly(styrene-r-benzocyclobutene-r-methyl methacrylate) (P(S-r-BCB-r-MMA)) as a thermally cross-linkable gate dielectrics. The P(S-r-BCB-r-MMA) showed high quality dielectric properties due to the negligible volume change during the cross-linking. The pentacene FETs based on the 34 nm-thick P(S-r-BCB-r-MMA) gate dielectrics operate below 5 V. The P(S-r-BCB-r-MMA) gate dielectrics yielded high device performance, i.e. a field-effect mobility of $0.25cm^2/Vs$, a threshold voltage of -2 V, an sub-threshold slope of 400 mV/decade, and an on/off current ratio of ${\sim}10^5$. The thermally cross-linkable P(S-r-BCB-r-MMA) will provide an attractive candidate for solution-processable gate dielectrics for low-voltage OFETs.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.6
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• pp.163-179
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• 2020

With the expansion of platform-based taxi service, mobility and convenience of users are getting better. However, due to profitability problem, marginalized areas in the supply of the service are expected to appear. As such, this study analyzed spatial marginalization of taxi service caused by imbalance in supply and demand during the night-time when public transportation service is suspended. According to hot-spot analysis of taxi, outskirt of a city and residential areas showed high vacancy and greater number of drop-offs compared to the number of pick-ups. On the contrary, they were confirmed low in the center and sub-centers of a city. Centrality analysis also showed a similar pattern with hot-spot analysis. Due to this, drivers may refuse to pick up a customer bound for an area with lower out-degree centrality compared to in-degree centrality as it might be difficult for the drivers to pick up another customer after dropping off the current customer. Thus, customers may need to wait for a taxi for a longer time. For this reason, improvement in spatial marginalization caused by mismatch of supply and demand is required. Also, the outcome of this study is expected to be utilized as a basic data.

• Journal of the Korean Institute of Rural Architecture
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• v.24 no.4
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• pp.67-75
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• 2022

The purpose of this paper is to provide basic data to Si and Gun preparing for rural agreements in the future through consideration and case analysis for rural conventions, such things as living standards, hierarchical analysis methods, and general rural development projects. In the 1970s, sporadic and one-off projects focused on individual projects were repeatedly carried out in rural areas, which were undergoing dramatic changes in population movement, land use, landscape, economic growth and living. The keyword of the government's policy has changed to a way that existing rural development projects are planned and promoted by local governments themselves in conjunction with the issue of autonomy and decentralization. In addition, with the introduction of Rural Convention, the central and local governments are striving to achieve common policy goals. However, due to the lack of understanding of the Rural Convention introduced as a pilot project in 2020, the lack of living areas setting-standards, unclear classification of hierarchical structure, and excessive goal consciousness for general agricultural and fishing village development projects remain, fading the original purpose of the Rural Convention. Therefore, this study analyzed the seven reports of the Gyeongsang region selected in the 2021 Rural Convention to identify the characteristics of living area, hierarchical structure analysis, and detailed projects (rural center revitalization project, basic living base development project) and provided them as basic data. As a result of the study, first, according to the results of the hierarchical structure analysis, the first class was derived from 6 out of 7 Si and Gun. This is judged to be the result of the current rural population, social, and economic problems. Second, according to the results of the division of living areas, it was confirmed that except for one local government in seven cities and counties, the remaining six local governments were divided into three single living areas and three two living areas. This is the result obtained through a comprehensive review by overlapping the results of various analyses such as hierarchical analysis and resident surveys and OD data, and shows a different form from the existing upper or related plans. It is judged that this is the result of including qualitative contents such as residents' opinions along with various analyses when determining the living area. Third, the proportion of the budget for rural center revitalization and basic living base development projects to the total project cost subject to the Rural Convention was 59.6%, which was relatively higher than that of other general agricultural and fishing village development projects. It is judged that it is preferred because the unit project cost is relatively high in Si and Gun, and that quantitative results can be visually shown after the project is terminated.

• Asia Marketing Journal
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• v.14 no.3
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• pp.69-102
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• 2012

Owing to increased number of luxury brand users, both genuine and counterfeit luxury product consumption continues to increase every year. Luxury brand is defined as use or display of a particular branded products which brings the ownership prestige apart from its functional utility(Grossmand and Shapiro 1988). Some luxury brands have imitations sold in marketplace due to their popularity. These imitations or counterfeits have been jumping on the bandwagon of the upturn in sales of their originals. The purpose of our study is to understand consumer's underlying motives to consume luxury brands, genuine and or counterfeits. To do this, we propose functional theories of attitudes, decision-making styles, and life attitudes to form the determining causes for different consumption choices of luxury brands: genuine brands, counterfeit brands, both genuine and counterfeit brands, and no consumption on luxury brands types. In proposed causal pathways, we examine moderated effects of socio-psychological factors to further investigate if consumer profiles would exert influences in causal relationships. From the existing theories of functional attitudes: value-expressive and social-adjustive attitudes, we developed and introduced a new measure of rationality-consumptive attitude. From the existing eight decision-making characteristics of consumer styles inventory(CSI), three measures of high-quality, hedonic-shopping, and price-shopping styles were primarily applied in the study along with newly introduced measure of 'high-price' being added, which makes four total. Seven life attitude measures of life purpose, life control, will to meaning, goal seeking, future mean to fulfill, life satisfaction, and religiosity were applied. Finally, such socio-psychological measures as age, gender, marital status, income, and age-gap between couples were assumed to function as moderators. With 430 valid study samples, ages from 20s to 50s, with more females(316) than males(114), with average personal possessions of 5 genuine and 9 counterfeit luxury brands, we conducted questionnaire survey. Results indicated that social-adjustive function is totally disappeared in the relationship due to current social trend of widespread consumptions on both genuine and counterfeit brands which in turn, make consumers feel less special on wearing or carrying them unlike in the past. Self-expressive function and rationality-consumptive functions act as strong catalysts for genuine brand consumption and counterfeit brand consumption, respectively. On consumers' decision-making styles, high-price sublation is the most powerful indicator anticipating counterfeit consumption, even more powerful than personal incomes. In life attitude, the overall model fit was not validated, and only life control and life satisfaction are proven to be significant on both genuine and counterfeit product consumptions. Employment of socio-psychological factors in the model improved understanding of users further. Young consumers tend to go for genuine products over counterfeits. Consumers in different income groups; low, medium and high, all significantly consume genuine products for reasons of different decision-making styles. The results indicated that consumers whose personal disposition is predisposed to consume products in the form of reflection of his or her personality, go only for genuine brands for quality reason, while consumers who rationally consume products for its function or usability, go only for counterfeits for high-price sublation reason. Meanwhile, both product users support for high-price orientation who are not well off.

• Asia Marketing Journal
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• v.15 no.1
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• pp.83-105
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• 2013

During recent decades, the number of mixed attribute products (henceforth mixed products), which have both utilitarian and hedonic benefits, has increased dramatically. Despite these products' growing popularity, academic research has paid little attention to them, and there remains a gap between theory and the real world. Hence, our study was undertaken to understand consumers' perceptions about and behaviors toward mixed products, as well as factors affecting the evaluation and choice of these products. We divided mixed attribute products into two categories: mixed utilitarian products (utilitarian products adding hedonic attributes) and mixed hedonic products (hedonic products adding utilitarian attributes). We then showed how adding different attributes affects consumers' perception, willingness to pay (WTP), and the choice of mixed attribute products compared to pure utilitarian or pure hedonic products. We conducted an experiment using a within-subject design. A total of 160 office workers and college students participated in the study. The pure utilitarian product used in the study was orange juice, and the mixed utilitarian product was carbonated orange juice. The pure hedonic product was chocolate, and the mixed hedonic product was polyphenol enriched chocolate. Results showed that consumers perceived a mixed utilitarian product to be less utilitarian, less pleasurable and more guilty than a pure utilitarian product. On the other hand, a mixed hedonic product was perceived to be more utilitarian, less pleasurable and less guilty than a pure hedonic product. Also, WTP for a mixed hedonic product was higher than WTP for a pure hedonic product, but WTP was lower for a mixed utilitarian product than for a pure utilitarian product. Furthermore, mixed hedonic products were likely to be evaluated more favorably when they were presented together with pure hedonic products, more so than when they were presented alone. Finally, when compared to low self-control participants, high self-control participants chose mixed hedonic products more frequently. The present study contributes to the existing literature on utilitarian and hedonic consumption by adding to the sparse literature on the consumption of products that have both utilitarian and hedonic purposes. Also, our research findings provide several useful implications for practitioners in related fields. First, the current study provides marketers with a useful guide for understanding consumers' perceptions of these types of products, and helps to predict how adding different attributes influences these products. Second, this study has examined the conditions that may moderate the evaluation and choice of hedonic base products and this finding will serve as a good reference for marketers of mixed hedonic products in marketing communication strategy, in-store marketing and targeting. Specifically, comparative advertising with a pure hedonic product will be beneficial for a mixed hedonic product. Also, displaying mixed hedonic products near pure hedonic products may enhance the effectiveness of in-store marketing of mixed hedonic products.

• Journal of the Korean Electrochemical Society
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• v.26 no.4
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• pp.43-55
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• 2023

Mass transport through nanoporous structures such as nanopores or nanochannels has fundamental electrochemical implications and many potential applications as well. These structures can be particularly useful for water treatment, energy conversion, biosensing, and controlled delivery of substances. Earlier research focused on creating nanopores with diameters ranging from tens to hundreds of nanometers that can selectively transport cationic or anionic charged species. However, recent studies have shown that nanopores with diameters of a few nanometers or even less can achieve more complex and versatile transport control. For example, nanopores that mimic biological channels can be functionalized with specific receptors to detect viruses, small molecules, and even ions, or can be made hydrophobic and responsive to external stimuli, such as light and electric field, to act as efficient valves. This review summarizes the latest developments in nanopore-based systems that can control mass transport based on the size of the nanopores (e.g., length, diameter, and shape) and the physical/chemical properties of their inner surfaces. It also provides some examples of practical applications of these systems.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.33 no.6
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• pp.255-260
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• 2023

As demanding the detection of explosive molecules, it is required to develop rapidly and precisely responsive sensors with ultra-high sensitivity. Since two-dimensional semiconductors have an atomically thin body nature where mobile carriers accumulate, the abrupt modulation carrier in the thin body channel can be expected. To investigate the effectiveness of WSe₂ semiconductor materials as a detection material for TNT (Trinitrotoluene) explosives, WSe₂ was synthesized using thermal chemical vapor deposition, and afterward, WSe₂ FETs (Field Effect Transistors) were fabricated using standard photo-lithograph processes. Raman Spectrum and FT-IR (Fourier-transform infrared) spectroscopy reveal that the adsorption of TNT molecules induces the structural transition of WSe₂ crystalline. The electrical properties before and after adsorption of TNT molecules on the WSe₂ surface were compared; as -50 V was applied as the back gate bias, 0.02 μA was recorded in the bare state, and the drain current increased to 0.41 μA with a dropping 0.6% (w/v) TNT while maintaining the p-type behavior. Afterward, the electrical characteristics were additionally evaluated by comparing the carrier mobility, hysteresis, and on/off ratio. Consequently, the present report provides the milestone for developing ultra-sensitive sensors with rapid response and high precision.