바이모달 저상굴절차량의 자동운전시스템을 위한 시뮬레이터 구현

류제(Ryu Je),황병일(Hwang Byoung-Il),이상남(Lee Sang-Nam),류희문(Ryu Hee-Moon),변윤섭(Byun Yeun-Sub) 한국철도학회 2009 한국철도학회 학술발표대회논문집 Vol.2009 No.5월

This paper discusses about the implementation of a simulator for the Navigation Control System(NCS) of bimodal tram. To operate a NCS of bimodal tram, values of all sorts of sensors installed in bimodal tram should be transmitted to the NCS, and the NCS calculates the measured sensor values to determine traveling direction, traveling speed, current position etc. The implementation of the simulator consists of a device applying driver’s input transaction function & virtual sensor program and a sub-rack device that controls communication with the NCS to evaluate navigation control function. The virtual sensor program can create routes (map), traveling profiles & seat information et cetera in order to transmit to the NCS, analyzes driver's input values and NCS output values to create virtual sensor values. The sub-rack device takes charge of communication with the NCS using CAN-OPEN, CAN-J1939, MVP protocols. This paper discusses about the implementation of the simulator and afterwards analyzes and evaluates the NCS simulation results.

Acquire to Kill : Evidence from “Real” Corporate Raiders

Hee Sub Byun,Kyung Suh Park,Woojin Kim,Eun Jung Lee 한국재무학회 2012 한국재무학회 학술대회 Vol.2012 No.09

This paper examines how malicious corporate raiders operating under poor investor protection environment may actually raid target firms’ resources through takeovers. Our perspective is distinct from both (1) conventional free cash flow theory where the central conflict of interests lies between bidder’s shareholders and managers, and (2) intra-business group tunneling where resources are transferred among existing member firms through non-arm’s length transactions. Using a large sample of publicly traded firms in Korea, we find that the probability of explicit looting through embezzlement or breach of fiduciary duty conditional on a recent change in control amounts up to 12%, almost 10 times as large as the corresponding probability when control remains intact. This finding is robust to controlling for the factors that induced the control change in the first stage. Such misbehaviors are more likely in targets with more liquid assets or multiple control changes. Market reactions to changes in control are initially positive but revert back within 6 months, mostly due to the persistent negative returns for those that later become subject to embezzlement or breach of duty. These findings suggest that market for corporate control may aggravate agency problems when investor protection is insufficient.

Impact of Controlling Shareholders on Corporate Social Responsibility under External Financial Constraints

Hee Sub Byun,Ji Hye Lee,Kyung Suh Park 한국재무학회 2013 한국재무학회 학술대회 Vol.2013 No.11

This study examines the relationship between the ownership of controlling shareholders and corporate social responsibility in Korea under external financial constraints. Empirical results show that a negative relationship is observed only in firms with fewer external financial constraints, while it disappears for firms with greater financial constraints. We reach a similar conclusion when we use the level of environmental management as a proxy for corporate social responsibility. These results confirm that external financial constraints act as a monitoring mechanism and mitigate the agency problem of controlling shareholders.

Product Market Competition and Ownership Structure in Business Groups : Evidence from Korean Chaebols

Hee Sub Byun,Ji Hye Lee,Kyung Suh Park 한국재무학회 2011 한국재무학회 학술대회 Vol.2011 No.11

This paper analyzes the effect of product market competition on controlling family’s voting rights and cash flow rights for member firms in business groups. Empirically, we confirm that member firms in competitive market have lower discrepancy, lower ownership of affiliates, and higher controlling family’s direct ownership than those in non-competitive market. This result means that product market competition disciplines controlling family on arranging the optimal ownership structure to maximize the shareholder value. On the other hand, such disciplinary effects of product market competition is mainly observed in member firms with lower market share in their own industry, in member firms of older business years, and in non-listed member firms.

How Does Product Market Competition Interact with Internal Corporate Governance? : Evidence from the Korean Economy

Hee Sub Byun,Ji Hye Lee,Kyung Suh Park 한국재무학회 2011 한국재무학회 학술대회 Vol.2011 No.09

We empirically test whether firms that belong to a business group behave differently from stand-alone firms in their decisions regarding internal corporate governance, given product market competition. Existing literature has ignored the possibility that firm characteristics may differentially affect the relationship. We find that the member firms of business groups maintain better internal corporate governance in a non-competitive environment, whereas stand-alone firms do so in a competitive environment. We also find that the positive effects of internal corporate governance on firm value are stronger in a non-competitive environment only for stand-alone firms. We ascribe the detected differences in corporate behavior and performance to differences in the level of competitive pressure to which firms are exposed. When we classify the firms by asset size or product market leadership, we observe a similar pattern.

The Market for Corporate Control in Emerging Economy : Disciplining Mechanism or Tunneling Device?

Hee Sub Byun,Woojin Kim,Eun Jung Lee,Kyung Suh Park 한국재무학회 2011 한국재무학회 학술대회 Vol.2011 No.11

This paper examines how the market for corporate control can be misused by malicious corporate raiders to expropriate target minority shareholders and creditors when investor protection is poor. Our perspective is distinct from the conventional free cash flow theory where the central conflict of interests lies between bidder’s shareholders and managers. Using a large sample of publicly traded firms in Korea, we find that explicit looting through embezzlement or breach of fiduciary duty as well as forced delisting is much more common in firms that recently went through a change in control. This finding is robust to controlling for the factors that induced the control change in the first stage. Such misbehaviors are more likely in firms with more liquid assets and stable performance. Market reactions to changes in control are significantly negative for those firms that later become subject to embezzlement, breach of duty or forced delisting. These finding strongly suggest that the market for corporate control in poor investor protection environment may not function as a disciplining mechanism but rather as a potential tunneling channel which raiders take advantage of.

How the Interaction between Product Market Competition and Corporate Governance affect Corporate Decision?

Hee Sub Byun,Ji Hye Lee,Kyung Suh Park 한국재무학회 2011 한국재무학회 학술대회 Vol.2011 No.11

This paper investigates the main channels of increased firm value when product market competition and corporate governance interact to affect corporate behavior and therefore firm value. Empirically, we confirm that corporate governance has a significantly negative effect on corporate payout and investment expenditure in non-competitive market while this effect disappears or decreases in competitive market. These results are robust to alternative measures of corporate governance and product market competition. We conclude that the substitution effect between product market competition and corporate governance on firm value and operating performance observed in existing literatures is due to the disciplined payout and investment policy.

생산함수를 활용한 주파수의 경제성 평가: 이동통신 산업을 중심으로

변희섭 ( Hee Sub Byun ) 정보통신정책학회 2021 정보통신정책연구 Vol.28 No.2

정부의 주파수 관리에 있어 시장 중심 체계의 도입이 시도되고 있다. 이러한 체계의 핵심은 시장원리, 즉, 경제성에 기초한 주파수의 할당 또는 재배치에 있다. 따라서 주파수의 경제성을 합리적으로 평가하기 위한 다양한 대안이 적극적으로 검토되어야 할 시점이다. 본 연구는 생산함수를 활용한 주파수의 경제성 평가 대안을 제안한다. 전 세계 이동통신 기업을 대상으로 한 실증분석결과, 주파수의 산출 탄력성은 0.05-0.07 수준으로 추정된다. 산출 탄력성은 주파수의 추가 투입이 매출액, 즉, 경제성을 정량적으로 어느 정도 증가시키는지를 시사한다. 이러한 논리를 바탕으로 경제성 평가 과정을 제안하며, 과거 1.8㎓ 대역 20㎒ 폭의 경매 사례와의 비교를 통해 실효성 있음을 확인한다. 본 연구의 결과는 정책적 함의를 가질 것으로 기대된다. 먼저, 본 연구의 논리는 현행 전파법의 주파수의 경제성을 매출액의 일부분으로 인식하는 과정과 유사하므로, 이에 대한 적정성을 이론적으로 검토하는데 활용이 가능할 것이다. 다음으로, 예상 매출액 추정의 어려움, 한계편익의 변화 가능성 등에 기인한 현행 체계의 제약을 주파수 할당량과 매출액의 동태적 변화를 고려하는 대안을 통해 일부 완화하는데 기여할 것으로 기대된다. Market-based spectrum management policy is used around the world. The core of this policy is the allocation and reallocation of spectrums based on economic factors. It is timely to actively examine various alternatives, and define the economic properties of spectrum management. This study proposes an alternative for estimating the economic properties of spectrums using the production function. Empirical analysis of mobile telecommunication companies around the world yields an output-input elasticity of spectrums - how much additional output (e.g. sales) is generated from an additional spectrum allocation - between 0.05 and 0.07. This study then proposes an economic estimation approach and confirms its effectiveness with respect to the winning price observed in the 1.8㎓ band auction. The findings have clear policy implications. Since the approach taken in this study is similar to the way the Korean Radio Waves Act views the economics of spectrums, the approach can be used to examine the propriety of laws. The current constraints in calculating the spectrum prices, such as the difficulty of estimating expected sales and the possibility of changes in marginal benefits, are partially relieved by the alternative approach that considers dynamic changes in the spectrum allocation size and sales.

주파수 이용효율 평가의 정합성과 개선방향

변희섭(Hee Sub Byun) 한국전자파학회 2023 한국전자파학회논문지 Vol.34 No.5

본 연구는 주파수 대역정비에 활용되는 이용효율 평가의 정합성을 분석하며, 개선방향을 제안한다. 이를 위해 본 연구는 크게 세 가지 접근을 시도한다. 먼저, 통계학 방법론에 근거하여 정합성을 평가하기 위한 체계를 제안하며, 상관성, 판별력과 정확성을 대안으로 도출한다. 제안된 체계의 실무적 활용성을 확인하기 위해 실증자료에 기초한 사례분석을 실시한다. 다음으로, 정책 목표를 달성하기 위한 개선방향으로, 평가지표 선정의 측면에서 정량지표 확대, 수준/변화 평가지표 조합, 보완 평가지표 활용, 규모효과 통제, 투입-산출 관계 고려를, 평가체계 구성의 측면에서 평가지표 가중치 적정성 검정과 사업용/비사업용 구분을 제안한다. 본 연구의 결과는 주파수 이용효율을 개선하기 위한 정책대안을 모색함에 있어 세부적 방향성 마련에 활용이 가능할 것이다. 더불어, 주파수 관리의 과학적 접근을 통해 정책의 신뢰성과 객관성을 제고하는 데 기여할 것이다. This study evaluated the consistency of the evaluation for the efficiency of spectrum usage and proposed improvement plans. First, a system for evaluating consistency was devised based on a statistical methodology, and the correlation, discrimination, and adequacy were derived as detailed criteria. Furthermore, a case study is conducted using empirical data to confirm the practical applicability of the proposed system. Moreover, improvement plans, such as the expansion of quantitative variables, a combination of variables reflecting level and change, utilization of complementary variables, control for size effects, consideration of the input-output relationship, weight adequacy test of variables, and classification of business and non-business usage, were devised. The findings of this study can contribute to formulating a detailed spectrum-management policy to promote the efficient use of each frequency band. Moreover, a scientific approach to spectrum management will enhance the reliability and objectivity of policies.

초고속인터넷 시장의 경쟁정책이 시장성과에 미치는 영향에 관한 실증분석

변희섭(Hee-Sub Byun),최진규(Jin-Kyu Choi),김상식(Sang-Sik Kim),이태원(Tae-Won Lee) 한양대학교 디지털경제연구소 2009 디지털경제연구 Vol.14 No.-

본 연구는 초고속인터넷 관련 경쟁정책이 시장성과에 미치는 영향을 분석한다. OECD 가입 25개국을 대상으로 구축한 동태적 패널자료를 바탕으로 실증분석을 실시한 결과, 설비기반경쟁도입년수가 길수록 보급가구비율은 증가하고, 속도당 요금은 하락하는 것으로 나타났다. 한편, 서비스기반경쟁을 의미하는 LLU(Local Loop Unbundling) 서비스의 제공은 보급가구비율에 유의한 영향을 미치지는 않았지만 속도당요금을 감소시키는 것으로 나타났다. 본 연구의 결과는 급속한 성장을 이룩해오다 현재에 이르러 정체되어있는 우리나라의 초고속인터넷 시장이 향후 추진해야할 정책입안에 대한 시사점을 제공하였다는데 의의를 갖는다.