• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.603-605
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• 1995

We present a novel method. to fabricate surface micromachined structures without their sticking on the substrate. An anhydrous HF/$CH_3OH$ vapor-phase etching (VPE) of sacrificial $SiO_2$ layers was employed to release 0.5-2 {\mu}m$ thick polysilicon cantilevers. The fabricated structures were observed using scanning electron microscope and 3-dimensional optical microscope. The results show that we can successfully make cantilever beams up to 1200{\mu}m$ long without sticking. Annealing effects on residual stress of polysilicon microstructures were also investigated. Anneal ins at 1100$^{\circ}C$ for 1 hour was found to be effective to release the residual stress of the polysilicon microstructures. These VPE and anneal ins techniques will be useful in surface micromachining technologies.

• International Journal of Computer Science & Network Security
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• v.21 no.4
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• pp.306-312
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• 2021

The main goal of higher education institutions is to present a high level of quality education to its students. This study uses data mining techniques to extract educational data from cumulative databases and used them to make the right decisions. This paper also aims to find the factors affecting students' academic performance in Majmaah University, KSA, during 2010 - 2017 period. The study utilized a sample of 6,158 students enrolled from two colleges, males and females. The results showed a high percentage of stumbling and dismissed between graduate and regular students where more than 62.5% failed to follow the plan. Only 2% of students scored distinction during their study of all graduated since their grade point average, secondary level, was statistically significant, where p<0.05. Dismissed percentage was higher among males. These results promoted some recommendations in which decision-makers could take them in considerations for better improvement of academic achievements: including of specialized programs to follow-up in regards to stumbling and failure. Utilization of different communication tools are needed to activate academic advisory for dismiss and dropout evaluation.

• Korean Institute of Interior Design Journal
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• no.13
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• pp.181-186
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• 1997

If you compare recent works in small commercial places along with the terms such as Post-Modernism, Late-Modernism, and Dismantling, to those of 60's and 70's, you will discover for sure that recent works try to model individually with 'surface'. Expressing the responses to the multilateral cultural desires is available through the organization of surface, so are the re-presentationsof classic notions by adding decorations to the vertical walls, which are different from modern constructions that have persisted on only space itself as a main point. These trends are various organizing techniques with forms, decorations, materials, color etc. and made the surface modeling develop. What a 'surface element' means as a concrete notion in a design process in a commercial place is enormous. So, it implies lots of notions and logic, and can be a strong message-conveying means as well as an expressional language. At this point of view, the research was limited to Facade, which is treated as a creational object to a designer all the time in order to study what kind of system the surface organization has in a small commercial place. This is to find out what kind of system the designer uses to make the spatial images, orders and forms through surface, but ultimately it is to discover the designer's basic tecniques that he or she uses when planning. To sum up, we have studied the meanings of the composition and the changes of the organization of Facade to analyze the organizing techniques in Pasad in a small commercial construction which designers planned as material. We have also investigated the organizing techniques of surface by examining and analyzing the elements of Facade organizing techniques, i.e. its form, decoration, material, pattern and color.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.10
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• pp.889-895
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• 2008

This paper presents a comprehensive mathematical analysis and simulation of trench IGBT with the help of PIN-PNP combinational model. Since trench IGBT is characteristically influenced by PIN diode, it may be almost impossible to analyze the trench IGBT using PNP-MOS modeling methods, even PIN-MOS techniques which neglect the hole current components coming into p-base region. A new PIN-PNP complementary cooperational model is developed in order to make up the drawbacks of existing models. It would allow us to make qualitative analysis as well as simulation about switching and on-state characteristics of 1,700 V trench IGBT. Moreover, if we improve the PIN diode effects through the optimization of trench structure, trench IGBT is expected to be one of the most promising devices in the not only high-voltage but also high speed switching device field.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.9
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• pp.1374-1379
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• 2015

Time Domain Reflectometry(TDR) using microwave bands, including broadband spectrum that occurs at the range of rates that start between partial discharge position it easier to make the techniques that could be measured. Partial discharge in the Gas Insulated Switchgear(GIS), the dielectric constant in the band more than GHz different the insulating material if you want to organize, and the insulating material regardless of how partial discharge position in the SF6 gas Partial Discharge by applying the heritability estimated its position, but the position error occurred about 23 percent of the existing way, correct in not suitable location tracking the outbreak PD. This technique the rate of other dielectric that make up the power apparatus heterology is measured at the function to slow the progression of the electromagnetic waves apart by calculating the partial discharge as the location, A simple way to track. Dielectric using other methods proposed new structure can calculate the speed of heritability PD is occurring can measure.

• The Journal of Korea Robotics Society
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• v.9 no.1
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• pp.57-66
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• 2014

This paper describes the design concept of a bio-inspired legged underwater and estimating its performance by implementing simulations. Especially the leg structure of an underwater organism, diving beetles, is fully adopted to our designing to employ its efficiency for swimming. To make it possible for the robot to both walk and swim, the transformable kinematic model according to applications of the leg is proposed. To aid in the robot development and estimate swimming performance of the robot in advance, an underwater simulator has been constructed and an approximated model based on the developing robot was set up in the simulation. Furthermore, previous work that we have done, the swimming locomotion produced by a swimming patten generator based on the control parameters, is briefly mentioned in the paper and adopted to the simulation for extensive studies such as path planning and control techniques. Through the results, we established the strategy of leg joints which make the robot swim in the three dimensional space to reach effective controls.

• Journal of Information Processing Systems
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• v.18 no.3
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• pp.428-442
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• 2022

A reliable automatic passenger counting (APC) system is a key point in transportation related to the efficient scheduling and management of transport routes. In this study, we introduce a lightweight head detection network using deep learning applicable to an embedded system. Currently, object detection algorithms using deep learning have been found to be successful. However, these algorithms essentially need a graphics processing unit (GPU) to make them performable in real-time. So, we modify a Tiny-YOLOv3 network using certain techniques to speed up the proposed network and to make it more accurate in a non-GPU environment. Finally, we introduce an APC system, which is performable in real-time on embedded systems, using the proposed head detection algorithm. We implement and test the proposed APC system on a Samsung ARTIK 710 board. The experimental results on three public head datasets reflect the detection accuracy and efficiency of the proposed head detection network against Tiny-YOLOv3. Moreover, to test the proposed APC system, we measured the accuracy and recognition speed by repeating 50 instances of entering and 50 instances of exiting. These experimental results showed 99% accuracy and a 0.041-second recognition speed despite the fact that only the CPU was used.

• Journal of KIISE:Software and Applications
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• v.30 no.1_2
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• pp.73-80
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• 2003

The Java programming language is designed for developing effective applications in a heterogeneous network environment. Major problem in Java is its performance. many attractive features of Java make the development of software easy, but also make it expensive to support ; applications written in Java are often much slower than their counterparts written in C or C++. To use Java`s attractive features without the performance penalty, sophisticated optimizations and runtime systems are required. Optimising Java bytecode has several advantages. First, the bytecode is independent of any compiler that is used to generate it. Second, the bytecode optimization can be performed as a pre=pass to Just-In-Time(JIT) compilation. Many attractive features of Java make the development of software easy, but also make it expensive to support. The goal of this work is to develop automatic construction of code optimizer for Java bytecode. We`ve designed and implemented a Bytecode Optimizer that performs the peephole optimization, bytecode-specific optimization, and method-inlining techniques. Using the Classfile optimizer, we see up to 9% improvement in speed and about 20% size reduction in Java class files, when compared to average code using the interpreter alone.

• Journal of Korean Neurosurgical Society
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• v.49 no.2
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• pp.97-101
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• 2011

Objective : It is technically difficult to treat wide-necked intracranial aneurysms by the endovascular method. Various tools and techniques have been introduced to overcome the related technical limitations. The purpose of this study was to evaluate the radiologic and clinical results of widenecked intracranial aneurysm treatment using the endovascular method. Methods : Fifteen aneurysms in 15 patients were treated by the endovascular method from October 2009 to August 2010. Seven patients presented with subarachnoid hemorrhage (SAH), seven patients had unruptured aneurysms, and one patient had an intracerebral hemorrhage and intraventricular hemorrhage due to an incompletely clipped aneurysm. The mean dome-to-neck ratio was 1.1 (range, 0.6-1.7) and the mean height-to-neck ratio was 1.1 (range, 0.6-2.0). We used double microcatheters instead of a stent or a balloon for the first trial. When we failed to make a stable coil frame with two coils, we used a stent-assisted technique. Results : All aneurysms were successfully embolized. Eleven aneurysms (73%) were embolized by the double microcatheter technique without stent insertion, and four aneurysms (27%) were treated by stent-assisted coil embolization. One case had subclinical procedure-related intraoperative hemorrhage. Another case had procedure-related thromboembolism in the left distal anterior cerebral artery. During the follow-up period, one patient (7%) had a recanalized aneurysmal neck 12 months after coil embolization. The recurrent aneurysm was treated by stent-assisted coil embolization. Conclusion : We successfully treated 15 wide-necked intracranial aneurysms by the endovascular method. More clinical data with longer follow-up periods are needed to establish the use of endovascular treatment for wide-necked aneurysm.

• Cross-Cultural Studies
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• v.45
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• pp.33-54
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• 2016

This study presents a comparative analysis of the calligrammic poetic dictions shown in the poems of the French poets Guillaume Apollinaire and Paul Eluard and in those of the Korean poet Lee Sang. They were adventurers in the avant-garde movement who used experimental techniques that led to futurism, expressionism, cubism, dadaism, and surrealism. They applied a typographic technique that combined pictorial arrangements of fonts, shapes of compositions and between lines, letters of the alphabet, mathematical symbols, and graphical elements, such as circles or lines, to make up a poem that also looked like a painting. Their works, valued as visual lyric poems, break up language and combine anti-poems. They rejected traditional poetic dictions or grammar, but developed a paratactic poem that freely uses letters and symbols. Their calligrammic poetic dictions arouse dynamic images like space extension. Lee Sang's calligrams seem like abstract paintings that apply geometric symbols like those used in technical drawings. As a result, crossing the boundaries between language and pictorial art by using experimental materials and techniques, their poems deconstruct the creative standards of rational and traditional poetic dictions, creating an adventurous, expressive technique. Their calligrammic, avant-garde poems introduced a new spirit of art into both French and Korean modern poetic literature.