• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.6
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• pp.351-359
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• 2015

Next-generation displays should be transparent and flexible as well as having high resolution and frame number. The main factor for active matrix organic light emitting diode and next-generation displays is the development of TFTs (thin-film transistors) with high mobility and large area uniformity. The TFTs used for transparent displays are mainly oxide TFT that has oxide semiconductor as channel layer. Zinc-oxide based substances such as indium-gallium-zinc-oxide has attracted attention in the display industry. In this paper, the mobility improvement of low cost oxide TFT is studied for fast operating next-generation displays by overcoming disadvantages of amorphous silicon TFT that has low mobility and poly silicon TFT that requires expensive equipment for complex process and doping process.

• The Journal of Korean Society for School & Community Health Education
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• v.12 no.3
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• pp.1-15
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• 2011

Objectives: We describe the development of a smoking and drinking prevention program for adolescents, using intervention mapping. Methods: The study sample consisted of 1,000 high school second-grade students from 6 high schools in Seoul. The PRECEDE model was applied for the needs assessment. We carried out a social diagnosis by assessing the factors such as the quality of life, happiness level, and satisfaction with school life; an epidemiological diagnosis on the perceived health status, stress levels, and priority of health issues; a behavioral diagnosis on the smoking and drinking rate and the intention to smoke and drink; and an educational diagnosis on knowledge, beliefs, attitudes, self-efficacy, outcome expectations, social norms and life skills. Results: The development process included a needs assessment, identifying factors that influence smoking and drinking among adolescents. Intention, knowledge, perceived norms, perceived benefit, perceived cost, perceived susceptibility, self-efficacy, and life skills were identified as determinants. Three performance objectives were formulated to describe what an individual needs to do in order to avoid smoking and drinking. Subsequently, we constructed an intervention matrix by crossing the performance objectives with the selected determinants. Each cell describes the learning objectives of the smoking and drinking prevention program. The program used methods from the transtheoretical model, such as consciousness raising, outcome expectations, self-reevaluation, self-liberation, counterconditioning, environmental reevaluation, and stimulus control. The program deals with the effects of smoking and drinking, self-improvement, decision making, understanding advertisements, communication skills, social relationships, and assertiveness. Conclusions: By using the process of intervention mapping, the program developer was able to ensure a systematical incorporation of empirical and new data and theories to guide the intervention design. Programs targeting other health-related behavior and other methods or strategies can also be developed using this intervention mapping process.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.1
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• pp.89-94
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• 2009

This paper proposes the algorithms that design the highly digital logic circuit and assign the code to each node of DCG(Directed Cyclic Graph) of length ${\zeta}$. The conventional algorithm have some problems, so this paper introduce the matrix equation from DCG of length ${\zeta}$ and proposes highly digital logic circuit design algorithms according to the DCG of length ${\zeta}$. Using the proposed circuit design algorithms in this paper, it become realized that was able to design from former algorithm. Also, making a comparison between the circuit using former algorithm and this paper's, we testify that proposed paper's algorithm is able to realize more optimized circuit design. According to proposed circuit design algorithm in this paper, it is possible to design current that DCG have natural number, so it have the following advantages, reduction of the circuit input/output digits, simplification of circuit composition, reduction of computation time and cost. And we show comparability and verification about this paper's algorithm.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.4
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• pp.223-230
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• 2015

As the Transportation Simplex Method of the general transportation problem are inapplicable to the large-scale unbalanced transportation problem, a commercialized linear programming package remains as the only viable means. There is, however, no method made available to verify the optimality of solutions attained by the package. This paper therefore proposes a simple heuristic algorithm to the large-scale unbalanced transportation problem. From a given problem of $31{\times}15$supply and demand areas, the proposed algorithm determines the number of demands areas for each supply area and executes on the latter in the ascending order of each of their corresponding demand areas. Next, given a single corresponding demand area, it supplies the full demand volume and else, it supplies first to an area of minimum associated costs and subsequently to the rest so as to meet the demand to the fullest extent. This initial optimal value is then optimized through an adjustment process whereby costs are minimized as much as possible. When tested on the $31{\times}15$cost matrix, the proposed algorithm has obtained an optimal result improved from the commercial linear programming package by 8.9%.

• The Journal of Korean Academy of Prosthodontics
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• v.22 no.1
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• pp.95-108
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• 1984

Even though the tarnishing and corrosion problems characteristic with dental silver-palladium alloy are not yet fully solved, it is recently widely used because of its low cost. However the effects of major alloying elements on the various properties of this system are not fully understood. The object of this research is to clarify the effects of In and Zn additives on the corrosion and tarnishing resistances and precipitation hardening behavior of this sytem, using electrodynamic polarization, immersion, and Vicker's microhardness test and X-ray diffraction and electron probe micro analysis methods. The obtained results were as follows: I. As indium content is increased, both the corrosion resistance in Cl-solution and microhardness are also increased while the tarnishing resistance is decreased. 2. As Zinc content is increased, the corrosion resistance is decreased, but tarnishing resistance is increased 3. At 70Ag-25Pd-2.5Zn-2.5In composition, the precipitation harding behavior was mot significant. The optimum aging temperature was $450^{\circ}C$ and the time was 2 hrs. The resulting specimen of this work carried 180VHN. 4. Under the heat treatment, the changes in the mechanical property are due to the changes in the shape and composition of dendrite matrix, namely, it is because of the precipitation hardening behavior which has been proved by electron probe micro analysis and optical microscopic finding.

• Membrane Journal
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• v.19 no.1
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• pp.63-71
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• 2009

In this study, polysulfone which has excellent mechanical and thermal stability with low cost was used for preparing a non-conducting polymer matrix as a reinforced composite membrane for fuel cell application. The membranes were prepared by phase separation method. Polymer concentration and retention time were controlled to investigate the effects on the membrane morphology. The resaltant membranes showed all sponge-like structure independent of polymer concentration. The mechanical and thermal stability were improved with increasing polymer concentration in contrast to the membrane porosity. As a result, the membranes prepared with the retention time for 2 mins using 20 wt% of polymer solution was suitable for a fuel cell compositite membrane providing optimum properties such as approximately 80% of high porosity, 1.3 MPa of tensile strength, and less than 1% of thermal shrinkage both machine and transverse direction.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.03a
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• pp.79-79
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• 2011

최근 플라스틱 제품의 사용후 폐기에서 발생 되는 환경적인 문제점들이 대두 되고 있는 가운데, 이러한 제품에 대한 친환경적인 재료 설계에 대한 요구가 거세지고 있는 실정으로 플라스틱 업계의 사활이 걸릴 정도의 중요한 문제로 부각되고 있다. 본 연구에서는 이러한 플라스틱 제품의 치명적인 환경적인 문제점을 극복하고자, Matrix 물질이 되는 플라스틱에서 부터 친 환경적인 생분해성 수지를 사용하면서, 물성의 강화제로써 천연물 유래의 여러 종류의 섬유를 사용하고자 하였다.가장 보편화된 생분해성 플라스틱인 지방족 폴리에스테르 계통의 생분해성 수지와 Polylactic acid에 대해 검토를 하였다. 지방족 폴리에스테르 의 경우는 기존 플라스틱 제품과 비교해서 유연하고, 신장율이 높고, PLA 대비 내열 사용한계 온도도 높아서 물성적인 측면에서 상당한 장점을 가지고는 있으나 가격이 매우 고가이므로, 기존 플라스틱을 대체하는 것에는 문제점이 있다. 반면 PLA의 경우 지방족 폴리에스테르 대비 절반 이하의 가격이고 기계적 강도 또한 매우 높기 때문에 기존의 플라스틱을 대체할 수 있는 가장 유력한 물질로 대두 되고 있으나, 사출물과 같은 충격이 요구되는 제품에 있어서는 PLA 고유의 약한 취성이 가장 큰 단점으로 지적되고 있다. 본 연구에서는 이러한 PLA를 기반으로 PLA의 장점이 기계적 강성을 유지하면서, 취성을 보완하기 위해 PBS를 혼합 할 수 있는 기술을 개발하였으며, 또한 원재료의 Cost를 줄이고, PBS 혼합에 따른 PLA의 기계적 강도 감소를 보완하기 위해 천연물 유래의 Wood fiber, Starch, Bamboo fiber, Cellulose fiber, Paper fiber 와 같은 각종 천연 Filler를 사용하여 기계적 기계적 강도 감소를 최소화 하였다.

• The KIPS Transactions:PartD
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• v.9D no.5
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• pp.779-788
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• 2002

There are many technically difficult issues in searching multimedia data such as image, video and audio because they are massive and more complex than simple text-based data. As a method of searching multimedia data, a similarity retrieval has been studied to retrieve automatically basic features of multimedia data and to make a search among data with retrieved features because exact match is not adaptable to a matrix of features of multimedia. In this paper, data clustering and its indexing are proposed as a speedy similarity-retrieval method of multimedia data. This approach clusters similar images on adjacent disk cylinders and then builds Indexes to access the clusters. To minimize the search cost, the hashing is adapted to index cluster. In addition, to reduce I/O time, the proposed searching takes just one I/O to look up the location of the cluster containing similar object and one sequential file I/O to read in this cluster. The proposed schema solves the problem of multi-dimension by using clustering and its indexing and has higher search efficiency than the content-based image retrieval that uses only clustering or indexing structure.

• Journal of KIISE:Software and Applications
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• v.31 no.9
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• pp.1246-1257
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• 2004

To find an optimal solution with genetic algorithm, it is desirable to maintain the population sire as large as possible. In some cases, however, the cost to evaluate each individual is relatively high and it is difficult to maintain large population. To solve this problem we propose a novel genetic algorithm based on fuzzy clustering, which considerably reduces evaluation number without any significant loss of its performance by evaluating only one representative for each cluster. The fitness values of other individuals are estimated from the representative fitness values indirectly. We have used fuzzy c-means algorithm and distributed the fitness using membership matrix, since it is hard to distribute precise fitness values by hard clustering method to individuals which belong to multiple groups. Nine benchmark functions have been investigated and the results are compared to six hard clustering algorithms with Euclidean distance and Pearson correlation coefficients as fitness distribution method.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.3
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• pp.211-219
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• 2014

Closed cracks are difficult to detect using conventional ultrasonic testing because most incident ultrasound passes completely through these cracks. Nonlinear ultrasound inspection using sub-harmonic frequencies a promising method for detecting closed cracks. To implement this method, a sub-harmonic phased array (PA) is proposed to visualize the length of closed cracks in solids. A sub-harmonic PA generally consists of a single transmitter and an array receiver, which detects sub-harmonic waves generated from closed cracks. The PA images are obtained using the total focusing method (TFM), which (with a transmitter and receiving array) employs a full matrix in the observation region to achieve fine image resolution. In particular, the receiving signals are measured using a laser Doppler vibrometer (LDV) to collect PA images for both fundamental and sub-harmonic frequencies. Oblique incidence, which is used to boost sub-harmonic generation, inevitably produces various surface waves that contaminate the signals measured in the receiving transducer. Surface wave interference often degrades PA images severely, and it becomes difficult to read the closed crack's position from the images. Various methods to prevent or eliminate this interference are possible. In particular, enhancing images with signal processing could be a highly cost-effective method. Because periodic patterns distributed in a PA image are the most frequent interference induced by surface waves, spatial frequency filtering is applicable for removing these waves. Experiments clearly demonstrate that the spatial frequency filter improves PA images.