• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.696-699
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• 2004

This paper proposes the Low Cost Class-E Converter with Power Conversion Operation of Piezoelectric Transformer. The Power Piezoelectric transformer capacity used in the proposed circuit is 15W and the electric equivalent circuit is presented. Class E type converter has some merits such as small component count, small size, and low cost. The topology has also ZVS conditions for main switch, thus in efficiency aspect, it is also competitive for commercial feasibility. The analysis and design guideline are suggested and also they are verified by experimental results.

• Journal of Ocean Engineering and Technology
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• v.11 no.4
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• pp.221-226
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• 1997

This study was carried out for the hull form development of G/T 340ton class high speed fishery patrol ship by Chosun University at the Circulating Water Channel cooperatively with Korea Maritime Service. Same size of 15knots class fishery patrol ship was selected as a parent form (Model number : CU-015), and modified fore and after body to be suitable for the operation at 20 knots. To minimize the breaking wave in the vicinity of fore body at high speed zone, high bulb nose and slender fore body hull form was chosen as an initial condition. Meanwhile, to ensure the engine room space keeping high resistance-propulsion performance, U-type stern hull form was developed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.11
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• pp.3997-4015
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• 2014

Radio frequency identification (RFID) is an emerging wireless communication technology which allows objects to be identified automatically. The tag anti-collision is a significant issue for fast identifying tags due to the shared wireless channel between tags and the reader during communication. The EPCglobal Class-1 Generation-2 which uses Q algorithm for the anti-collision is widely used in many applications such as consumer electronic device and supply chain. However, the increasing application of EPCglobal Class-1 Generation-2 which requires the dynamic environment makes the efficiency decrease critically. Furthermore, its frame length (size) determination and frame termination lead to the suboptimal efficiency. A new anti-collision algorithm is proposed to deal with the two problems for large-scale RFID systems. The algorithm has higher performance than the Q algorithm in the dynamic environment. Some simulations are given to illustrate the performance.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.1
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• pp.132-137
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• 2007

Jacket transforms are a class of transforms which are simple to calculate, easily inverted and are size-flexible. Previously reported jacket transforms were generalizations of the well-known Walsh-Hadamard transform (WHT) and the center-weighted Hadamard transform (CWHT). In this paper we present a new class of jacket transform not derived from either the WHT or the CWHT. This class of transform can be applied to any even length vector, and is applicable to finite fields and is useful for constructing error control codes.

• Journal of Species Research
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• v.9 no.1
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• pp.68-76
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• 2020

We identified 22 ciliate species, including five unrecorded ciliate species, from temporary ponds on a grass lawn. The five unrecorded species are as follows: class Nassophorea - Pseudomicrothorax agilis Mermod, 1914, Nassula exigua Kahl, 1931, class Colpodea - Cyrtolophosis mucicola Stokes, 1885, Maryna ovata (Gelei, 1950) Foissner, 1993, and class Spirotrichea - Meseres corlissi Petz & Foissner, 1992. Most of these 22 ciliate species disappeared from a raw culture within a few days (probably encystment), and a few cells were available from some species that resulted in incomplete identifications (e.g., genus-level). About the unrecorded five ciliate species, they are small in size (<60 ㎛ in vivo), and two of them live in a hyaline dwelling-tube, which is easily deserted by a cell with a stress. Their taxonomic classification is summarized as three classes, five orders, five families, and five genera. Here, we provide brief descriptions, micrographs of their morphology, and some remarks.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.324-333
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• 2018

The aim of this study was to investigate the latent classes and predictors of chronic diseases such as hypertension, dyslipidemia, arthritis, thyroid disease, depression, atopy, allergy, and diabetes. The subjects of this study were Korean citizens who participated in the Korea National Health and Nutrition Examination Survey in 2014. Stratified cluster sampling method was used with a sample size of 7,550. Latent hierarchy analysis was applied to this data. Four classes were identified. Class 1 consisted of participants with hypertension and diabetes. Class 2 consisted of participants with atopy and allergies. Class 3 consisted of participants with dyslipidemia, arthritis, thyroid disease, and depression. Class 4 consisted of participants without any chronic diseases. In comparing Class 1 to Class 4, age, physical activity, self-management, obesity, and presence of high cholesterol were found to be significant. In comparing Class 2 to Class 4, gender, age, and education level were significant. When Class 3 was compared to Class 4, gender, age, pain and discomfort, as well as high cholesterol were found to be significant. Diabetes and hypertension should be treated as comorbid conditions, applying integrated treatments involving effective drug treatment, diet, and physical activity programs. Atopy was found to be strongly correlated with allergies. Thyroid disease was found to coexist with dyslipidemia and arthritis, along with having a strong correlation to depression. Age-appropriate preventive measures can help reduce the risk of chronic diseases.

• Korean Journal of Mathematics
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• v.4 no.2
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• pp.101-115
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• 1996

In this paper, we will show that the minimal number of generators of any four dimensional, faithful, $\mathcal{B}$(Schur algebra of size 4)-module is two. This result can be applied to classify the isomorphism classes of the class {$\mathcal{B}{\ltimes}N^2{\mid}N$ is a faithful, $\mathcal{B}$-module with $dim_k(N)=4$}.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.854-857
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• 2005

We developed new circuit architecture for reducing the power consumption and chip-size of driver ICs. In this paper we describe a new drive scheme, based on the concept of time -sharing output and optimal circuit design based on color resolution. In case of 132 x 176-pixel class, we used only 8 O p-A mps for a 262-k color display.

• Computers and Concrete
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• v.20 no.2
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• pp.197-204
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• 2017

Typically, high lime fly ash (Class C) has been characterized as a fly ash, which at lower replacement levels is not as effective as the low lime (Class F) fly ash, in mitigating alkali-silica reaction (ASR) in portland cement concrete. The influence of fineness of Class C, obtained by grinding virgin fly ash into finer particles, on its pozzolanic reactivity and ASR mitigation performance was investigated in this study. In order to assess the pozzolanic reactivity of mortar mixtures containing virgin or ground fly ashes, the strength activity index (SAI) test and thermo-gravimetric analysis (TGA) were conducted on the mortar cubes and paste samples, respectively, containing virgin fly ash or two ground fly ashes. In addition, to evaluate any improvement in the ASR mitigation of ground fly ashes compared to that of the virgin fly ash, the accelerated mortar bar test (AMBT) was conducted on the mortar mixtures containing different dosages of either virgin or ground fly ashes. In all tests crushed glass aggregate was used as a highly reactive aggregate. Results from this study showed that the finest fly ash (i.e., with an average particle size of 3.1 microns) could increase the flow ability along with the pozzolanic reactivity of the mortar mixture. However, results from this study suggested that the fineness of high lime fly ash does not seem to have any significant effect on ASR mitigation.

• Progress in Superconductivity and Cryogenics
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• v.5 no.3
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• pp.48-51
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• 2003

HTS power transmission cable is expected to transport large electric power with a compact size. We are developing a 3-core, 22.9 kV, 50 MVA class HTS power cable, and each core consists of a conductor and shield wound with Bi-2223 tapes, electrical insulation with laminated polypropylene paper (LPP) impregnated with liquid nitrogen. This paper describes the design and experimental results of the model cable for the 22.9 kV, 50 MVA class HTS power transmission cable. The model cable was used the SUS tapes instead of HTS tapes because of testing the electrical characteristics only. The model cable was 1.3 m long and electrical insulation thickness was 4.5 mm. The model cable was evaluated the partial discharge (PD), AC and Impulse withstand voltage in liquid nitrogen. The AC and Impulse withstands voltage and PD inception stress was satisfied with the standard of Korea Electric Power Corporation (KEPCO) in the test results. The 3-core 22.9 kV, 50 MVA class HTS power cable has been designed and manufactured based on these experimental results.