• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.671-676
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• 2003

This paper presents 3-phase current regulation of SR motor by only single current sensor. The conventional drive system of SR motor has a current sensor per each phase. In this paper, The asymmetric bridge converter which Is able to control independently phases and be excited simultaneously is used fs the driver system for 6/4 poles SR motor. And the sensor Is replaced 3 sensors of each phase with only one on bus line of converter so as to detect current of every phase. A drive logic circuit is designed on EPLD with Delta modulation using a fixed frequency This technique is verified through simulation and experiment.

• Journal of Power Electronics
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• v.12 no.2
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• pp.258-267
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• 2012

An interleaved single-stage AC/DC converter with a boost converter and an asymmetrical half-bridge topology is presented to achieve power factor correction, zero voltage switching (ZVS) and load voltage regulation. Asymmetric pulse-width modulation (PWM) is adopted to achieve ZVS turn-on for all of the switches and to increase circuit efficiency. Two ZVS half-bridge converters with interleaved PWM are connected in parallel to reduce the ripple current at input and output sides, to control the output voltage at a desired value and to achieve load current sharing. A center-tapped rectifier is adopted at the secondary side of the transformers to achieve full-wave rectification. The boost converter is operated in discontinuous conduction mode (DCM) to automatically draw a sinusoidal line current from an AC source with a high power factor and a low current distortion. Finally, a 240W converter with the proposed topology has been implemented to verify the performance and feasibility of the proposed converter.

• The Korean Journal of Financial Management
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• v.25 no.3
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• pp.79-109
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• 2008

According to asymmetric information hypothesis (for example, Ross (1977), Myers and Majluf (1984)), the impact of seasoned equity offering (SEO) announcement on the stock price depends mainly on the informational market efficiency. Despite of the importance of this fact, most of the previous SEO-related studies have done under the assumption of equal informational market efficiency among sample firms. This study intends to solve this problematic assumption and explores the real impact of SEO announcement on the stock prices. For this purpose, we divide 122 SEO firms into two subgroups; one with firms from KOSPI200 and the other including firms from the rest of KOSPI, assuming the former is more informationally efficient than the latter. Different from the US market-based study demonstrating short-and long-term negative price impacts of SEO announcement, most of the Korean market-based ones show price increases up until the announcement and decreases just after the announcement and in the long run. These previous studies attribute this difference to the different market system and regulation between them. Our results indicate that this discrepancy can be attributed to the different degree of market efficiency as well as the different market system and regulation.

• BMB Reports
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• v.40 no.5
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• pp.617-624
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• 2007

Protein arginine methylation is a posttranslational modification involved in various cellular functions including cell signaling, protein subcellular localization and transcriptional regulation. We analyze the protein arginine methyltransferases (PRMTs) that catalyze the formation of methylarginines in porcine brain. We fractionated the brain extracts and determined the PRMT activities as well as the distribution of different PRMT proteins in subcellular fractions of porcine brain. The majority of the type I methyltransferase activities that catalyze the formation of asymmetric dimethylarginines was in the cytosolic S3 fraction. High specific activity of the methyltransferase was detected in the S4 fraction (high-salt stripping of the ultracentrifugation precipitant P3 fraction), indicating that part of the PRMT was peripherally associated with membrane and ribosomal fractions. The amount and distribution of PRMT1 are consistent with the catalytic activity. The elution patterns from gel filtration and anion exchange chromatography also indicate that the type I activity in S3 and S4 are mostly from PRMT1. Our results suggest that part of the type I arginine methyltransferases in brains, mainly PRMT1, are sequestered in an inactive form as they associated with membranes or large subcellular complexes. Our biochemical analyses confirmed the complex distribution of different PRMTs and implicate their regulation and catalytic activities in brain.

• Environmental and Resource Economics Review
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• v.29 no.1
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• pp.47-89
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• 2020

We introduce a simple theoretical model to analyze the welfare impact of a competition policy in the natural gas market in South Korea. An incumbent monopolistic firm currently owns essential facilities, but the competition policy mandates that the firm provide open access to any entrant firm, charging an access fee. When no regulation is imposed on the fee pricing, this policy increases social welfare as well as the profit of the incumbent firm. When the pricing is regulated, however, social welfare depends on whether there is information asymmetry between the government and the firm regarding the operating cost of the facilities. If the government has complete information, social welfare can be maximized by choosing the optimal prices. Otherwise, the government has to set the prices based on the information that the firm delivers. We formulate a Bayesian game to analyze this case and identify a set of perfect Bayesian equilibria to compare social welfare.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.4
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• pp.356-361
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• 2008

The conventional drive system of SRM has a current sensor per each phase. The torque demand signal generated by the outer control loop is translated into individual current reference signal for each phase. The torque is controlled by regulating these currents. Using the SRM in a variable-speed control, the phase currents are generally regulated to achieve a square wave. The simplest form of current regulation uses fixed frequency delta modulation of the phase voltages. The aim of this paper is to regulate 3-phases current of SRM by only single current sensor using delta modulation with digital chip. In this paper, the asymmetric bridge converter which is able to control independently phases and be excited simultaneously is used as the driver system for 6/4 poles SRM. And the current sensor is replaced 3 sensors of each phase with only one on bus line of converter so as to detect current of every phase. The proposed delta modulation technique has been implemented in a simple digital logic circuit using EPLD(Electrically Programmable Logic Device). This method is verified through simulation and experiment results.

• The Journal of the Korea Contents Association
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• v.11 no.7
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• pp.192-209
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• 2011

This study looked into coping strategies of local terrestrial broadcasting companies in the media market, since the introduction of comprehensive programming channels was confirmed. Local terrestrial broadcasting companies vulnerable to market competitiveness are driven more out to the difficulty of survival in a limited advertising market with the advent of comprehensive programming channel. and Local terrestrial broadcasting receive discriminative application than comprehensive programming channel. They have reverse discrimination in must-carry, broadcasting area, programming regulation, advertisement regulation, broadcasting development fund. Hence, Local terrestrial broadcasting needs diverse countermeasures at difficult media circumstances. Above all, Competitive content reinforcement is desperately needed. That's why content distribution structure needs diversification. And, It is necessary for local terrestrial broadcasting companies to diversify the content distribution system. As a way to expand distribution structure of local broadcasting, the introduction of local programming regulations for total amount will be highlighted in the nationwide network program. The mandatory policy that programs produced by local terrestrial broadcasting companies will be broadcast regularly in prime time through a nationwide network is an example. In addition to developing high content independently, 2nd Multiple channels of distribution is needed. It has to be supplied to various platforms including local broadcasting, SO and etc. In addition, it is necessary to activate regional co-production program between local terrestrial broadcasting companies and regions. Time rate between central stations and local terrestrial broadcasting companies must be distributed practically. And also, local terrestrial broadcasting companies in addition to ad revenue model to themselves and their own businesses by expanding the sponsorship to strengthen the competitiveness will have to nurture self-sustaining. Moreover they must have enlarge economy of scale through widen of broadcasting area.

• Journal of Internet Computing and Services
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• v.15 no.5
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• pp.123-132
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• 2014

Internet is composed of many independent networks referred to as Internet Service Providers (ISPs) and each provider is generally interconnected based on a commercial agreement. Though many countries are engaged in deregulation in internet interconnection, there is still debate whether the large ISPs are unwilling to peer with small providers, have incentives to lower the quality of data transmission of transit operators or set the interconnection charge regarding the actual costs incurred by the interconnection. Korean government introduced regulations in internet interconnection after observing noticeable anti-competitive behaviors from 2005. This paper analyzes whether there is margin squeeze problem/market concentration, and suggests political proposals in Korean regulation status.

• Journal of Life Science
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• v.25 no.11
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• pp.1223-1229
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• 2015

Oryzalin is a dinitroaniline herbicide, which disrupts the arrangement of microtubules. Microtubules and microfilaments are cytoskeletal components that are thought to play a role in the sedimentation of statoliths and the formation of cell walls. Statoliths regulate the perception of gravity by columella cells in the root tip. To determine the effect of oryzalin on the gravitropic response, ethylene production in primary roots of maize was investigated. Treatment with 10^-4 M oryzalin to the root tip inhibited the growth and gravitropic response of the roots. However, the treatment had no effect on the elongation zone of the roots. An application of 10^-4 M oryzalin for 15 hr to the root tip caused root tip swelling. The application of 1-aminocycopropane-1-carboxylic acid (ACC), a precursor of ethylene, to the root tip also inhibited the gravitropic response. To understand the role of oryzalin in the regulation of the growth and gravitropic response of roots, ethylene production in the primary roots of maize was measured following treatment with oryzalin. Oryzalin stimulated ethylene production via the activation of ACC oxidase (ACO) and ACC synthase (ACS), and it increased the expression of ACO and ACS genes. Indole-3-acetic acid (IAA) played a key role in the asymmetric elongation rates observed during gravitropism. The results suggest that oryzalin alters the gravitropic response of maize roots through modification of the arrangement of microtubules. This might reduce the distribution of IAA in the upper and lower sides of the elongation zone and increase ethylene production, thereby inhibiting growth and gravitropic responses.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.5
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• pp.3037-3040
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• 2013

Introduction: Mammography is the most basic modality in breast cancer imaging. However, the overlap of breast tissue depicted on conventional two-dimensional mammography (2DMMG) may create significant obstacles to detecting abnormalities, especially in dense or heterogeneously dense breasts. In three-dimensional digital breast tomosynthesis (3DBT), tomographic images of the breast are reconstructed from multiple projections acquired at different angles. It has reported that this technology allows the generation of 3D data, therefore overcoming the limitations of conventional 2DMMG for Western women. We assessed the detectability of lesions by conventional 2DMMG and 3DBT in diagnosis of breast cancer for Japanese women. Methods: The subjects were 195 breasts of 99 patients (median age of 48 years, range 34~82 years) that had been pathologically diagnosed with breast cancer from December 20, 2010 through March 31, 2011. Both conventional 2DMMG and 3DBT imaging were performed for all patients. Detectability of lesions was assessed based on differences in category class. Results: Of the affected breasts, 77 (75.5%) had lesions assigned to the same categories by 2DMMG and 3DBT. For 24 (23.5%) lesions, the category increased in 3DBT indicating improvement in diagnostic performance compared to 2DMMG. 3DBT improved diagnostic sensitivity for patients with mass, focal asymmetric density (FAD), and architectural distortion. However, 3DBT was not statistically superior in diagnosis of the presence or absence of calcification. Conclusions: In this study, 3DBT was superior in diagnosing lesions in form of mass, FAD, and/or architectural distortion. 3DBT is a novel technique that may provide a breakthrough in solving the difficulties of diagnosis caused by parenchyma overlap for Japanese women.