Reputation in Market Participation Games

Kim,Youngse 延世大學校經濟硏究所 1995 延世經濟硏究 Vol.2 No.1

We examine reputation equilibria of what we call participation games, that have many economic examples, such as entry deterrence and product quality game. By perturbing the original game with types, we show that the lower bound of the single long run player's payoff is almost his Stackelberg commitment payoff in the limit as the finite horizon grows. Discontinuity exists between the infinite horizon and the limiting finite horizon problem. Our result is robust to a model modification in which the long run player announces the payoff structure before the whole game begins so that the rational type of long run player has to mimic not only the strategy of the Stackelberg commitment type but also the initial payoff announcement.

공정제어시스템의 사이버보안 위험 노출 현황 및 대응방안 연구

김영세 ( Youngse Kim ),박진형 ( Jinhyung Park ),김상기 ( Sangki Kim ),김병직 ( Byungjick Kim ),이준원 ( Joonwon Lee ),박교식 ( Kyoshik Park ) 한국화학공학회 2022 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.60 No.4

오늘날 대부분의 국내 석유화학 산업에서 사용되고 있는 공정제어시스템은 Windows 플랫폼 기반을 사용하고 있다. 개방형 기술에 따른 위험 노출이 증가하고 있지만, 사이버 공격에 대한 인식 부족과 오해로 인해 각종 사이버 공격에 대비하는 기업이 많지 않다. 본 연구는 석유화학 공정제어시스템이 OT 사이버보안 취약성에 얼마나 노출된 상태에서 운영 중인지를 조사하였으며, 보안 취약점을 감소시킬 수 있는 현실적인 방법을 제시하고자 하였다. 공정제어시스템의 사이버 위협 상태를 확인하기 위하여, 주요 사이버 위협 인자인 Windows 플랫폼에 대한 취약점을 확인하였으며 이를 위하여 국내 주요 3개 DCS 공급자와 635개 시스템의 Windows 플랫폼 단종 여부를 조사하였다. 조사결과 조사 대상의 77.5%가 아직도 이미 단종된 Windows 플랫폼으로 운영 중인 것으로 확인되어 공정제어 시스템이 보안 위협에 취약한 상태로 운영 중인 것으로 확인되었다. 이러한 사이버 위협에 능동적으로 대처하기 위해서는 미국과 같은 선진국에서 시행하고 있는 주요 석유화학 시설에 대한 중요기반시설 지정과 같은 법률적인 규제가 필요할 것으로 판단되며, 기존 DCS 공급자가 제공하는 보안 솔루션을 적극적으로 도입하여 공정제어시스템에 대한 보안 위협을 적극적으로 감소시키려는 노력이 필요한 시점이라고 판단된다. Process control systems used in most domestic petrochemical corporates today are based on the Windows platforms. As technology leans toward opened environment, the exposure risk of control systems is increasing. However, not many companies are preparing for various cyberattacks due to lack of awareness and misunderstanding of cyber intrusion. This study investigated the extent of how much exposed the petrochemical process control system is to security threats and suggested practical measures to reduce OT cybersecurity vulnerabilities. To identify the cyber threat status of process control systems, vulnerabilities of the Windows platform, a principal cyber threat factor, have been analyzed. For research, three major DCS providers in Korea and the discontinuation of Windows platform of 635 control systems were investigated. It was confirmed that 78% of the survey subjects were still operating in the discontinued windows platforms, and those process control systems were operated in a state vulnerable to cyber intrusions. In order to actively cope with these cyber threats, legal regulations such as designation of critical infrastructure for major petrochemical facilities which is implemented in advanced countries such as the United States are needed. Additionally, it is necessary to take the initiative in eradicating security threats to the process control systems by aggressively introducing security solutions provided from existing DCS suppliers. This paper was submitted to Professor Ko JaeWook's retirement anniversary issue.

Packet Signing 기법을 활용한 SCTP 방식의 RADIUS 프로토콜

김영세 ( Youngse Kim ),김기천 ( Keecheon Kim ) 한국정보처리학회 2016 한국정보처리학회 학술대회논문집 Vol.23 No.2

Remote Authentication Dial-In User Service (RADIUS)은 원격지의 사용자들을 인증하기 위한 대표적인 프로토콜이다. 기존의 RADIUS인증은 인증 서버가 클라이언트 IP, URI정보와 같은 데이터 통신의 기본사항만을 확인한 후 세션을 설정한다. 하지만, 악의적인 공격자가 IP 혹은 URI정보를 위/변조해서 인증을 요청하거나 반복적인 인증요청을 통한 DOS(Denial Of Service)공격을 수행할 경우 부적절한 인증, 사용자의 인증시간 지연 및 실패와 같은 심각한 문제가 발생할 수 있다. 본 논문에서는 클라이언트와 서버가 공유하는 데이터의 Hash값을 검증한 후, Packet Signing 방식을 활용해서 유효한 사용자에게만 서버접근을 허용하는 방안을 제안한다.

효율적인 비상대응을 위한 Process High Alarm의 Priority 분석

김영세 ( Youngse Kim ),조규선 ( Gyusun Cho ),전진우 ( Jinwoo Jun ),김병직 ( Byungjick Kim ),이준원 ( Joonwon Lee ),박교식 ( Kyoshik Park ) 한국화학공학회 2020 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.58 No.4

본 연구에서는 국내 석유화학산업에 설치 운영 중인 DCS (Distributed Control System)에 설정되어 실제 운전에 적용하고 있는 PV high trip point에 설정된 alarm의 우선순위를 ISA 18.2 국제규격 또는 EEMUA 191 guideline 에서 제시하고 있는 기준과 비교 분석하여 현재 사용 중인 공정 alarm의 우선순위 관리상태를 확인하는 것이 목적이다. 공정 문제 발생 시 과도하게 설정된 high alarm이 짧은 시간 안에 운전자에게 제공되어 최우선으로 처리해야 할 alarm을 분별하기 어려워지는 상황이 발생하게 된다. 이로 인하여 운전자가 정해진 시간 안에 적절한 조치를 진행하지 못할 가능성이 커지고 예상하지 못한 공정의 shutdown이나 공정사고로 이어지는 사례가 다수 보고되었다. 그리하여 본연구에서는 alarm 관리에 관련된 국제규격을 소개하고 국내 석유화학산업 현장에 사용하고 있는 alarm 관리 수준을 확인하여 향후 국가 산단의 석유화학 공정에 발생할 수 있는 잠재적 위험을 알리고 위험 요소를 감소시킬 방안을 제시하고자 한다. The purpose of this study is to check the priority control status of the current operation process alarm by comparing the priority of the alarm set up in PV high trip point, which is being installed and operated in the domestic petrochemical industry, with the criteria presented in ISA 18.2 International Standard or EEMUA 191 Guidelines. In the event of a process problem, excessively set high alarm is provided to the driver in a short period of time, making it difficult to identify the alarm that needs to be handled first. As a result, it is likely that the operator will not be able to carry out appropriate actions within the specified time frame, and many cases have been reported leading to unexpected process shutdowns or process accidents. Therefore, this study aims to introduce international standards related to alarm management and identify the level of alarm control used at the domestic petrochemical industry site to inform potential risks that may occur in the petrochemical process of the national industrial complex in the future and suggest ways to reduce risk factors. This paper was submitted to Professor Lee Inbeom’s retirement anniversary issue.

Signaling Valence by Positive and Negative Campaigns

S. David Kim,Youngse Kim 한국계량경제학회 2020 JOURNAL OF ECONOMIC THEORY AND ECONOMETRICS Vol.31 No.3

This paper aims at analyzing both positive and negative politicalcampaigns which affect voters’ perception about candidate valence. Considerthe situation where candidates know valences each other but the voters cannotobserve one candidate’s valence. We characterize perfect Bayesian equilibria,which depend on the cost of positive campaign for the candidate and the cost ofnegative campaign against the opponent. The cost may be interpreted as the campaignbudget constraint or the risk from backfire. We show that there always exista pooling equilibrium and, for a wide range of parameters, a separating equilibrium.If positive campaign costs sufficiently less by the candidate with highervalence, the high valence candidate conducts positive campaign whereas the lowvalence candidate does not. More important, if negative campaign against thehigh valence opponent is sufficiently costly or risky due to backfire, the incumbentconducts negative campaign against a low valence challenger but notagainst a high valence one. We also show that, the smaller the valence differenceis between two candidates, the larger the platform divergence becomes on theequilibrium.

Paedoksan ameliorates allergic disease through inhibition of the phosphorylation of STAT6 in DNCB‑induced atopic dermatitis like mice

Lee Sang Heon,Oh Youngse,Bong Sim-Kyu,Lee Jin Woo,Park No-June,Kim Young-Joo,Park Hyun Bong,Kim Yong Kee,Kim Seung Hyun,Kim Su-Nam 한국응용생명화학회 2023 Applied Biological Chemistry (Appl Biol Chem) Vol.66 No.-

Various allergic diseases such as atopic dermatitis (AD), allergic rhinitis, and asthma are considered incurable conditions that have yet to be fully conquered. Paedoksan (PDS), an herbal preparation consisting of 14 medicines, displays effective anti-inflammatory and anti-allergic properties, yet its underlying molecular mechanism is unknown. This study aims to uncover PDS’s mechanism for treating allergic diseases and suggest its therapeutic potential. Through a network pharmacological prediction, its impact on signal transducer and activator of transcription 6 (STAT6) regulation, a sub-mechanism of interleukin 4 (IL-4), a major inflammatory cytokine involved in degranulation and allergy, was investigated in RBL-2H3 cells and an atopic mouse model. PDS inhibits immunoglobulin E (IgE)-induced degranulation and STAT6 phosphorylation evoked by IL-4 in granulocytes. The downregulation of phospho-STAT6 and thymic stromal lymphopoietin (TSLP) by PDS was confirmed in 2,4-dinitrochlorobenzene (DNCB)-induced mouse skin. The results demonstrate that PDS exhibited remarkable effects on degranulation and STAT6 phosphorylation in RBL-2H3 cells, as well as in an atopic mouse model. Furthermore, the main active components from PDS based on chromatographic analysis showed good accordance with PDS’s effects on RBL-2H3 cells. In summary, these findings collectively suggest that PDS holds the potential to effectively suppress inflammatory and allergic reactions by obstructing the target IL-4 protein and its downstream effects, as elucidated through a network pharmacological analysis.

Malignant Peripheral Nerve Sheath Tumor in Descending Colon - A Case Report -

YoungS. Park,SungJig Lim,WooHo Kim,EuiKeun Ham 대한병리학회 2002 Journal of Pathology and Translational Medicine Vol.36 No.3

We report a unique case of malignant peripheral nerve sheath tumor (MPNST) of colon, not associated with neurofibromatosis or parasite infection. The tumor presented as an encircling mass in descending colon causing obstruction with numerous metastatic lesions in a 43-year-old man. The tumor was largely composed of spindle cells which showed strong positivity for vimemtin, S-100 protein and Leu-7. The tumor often exhibited epithelioid feature where tumor cells were weakly positive for cytokeratin.

전력산업 계통운용보조서비스의 효율적 비용분담

김영세 한국산업조직학회 2003 産業組織硏究 Vol.11 No.3

본 논문은 경제적 효율성을 극대화하는 전력 계통운용보조서비스의 설계와 비용분담 방안을 불완전정보와 도덕적 헤이의 측면에서 분석한다. 또한 현행 비용분담 방안을 경제적 효율성의 측면에서 평가한다. 만약 발전회사들이 요구하는 보조서비스 비용 전액을 송배전회사나 최종소비자가 부담하는 경우, 발전회사들은 유지보수노력을 과소하게 유지하고자 하는 도덕적 헤이 유인을 갖게 된다. 이는 발전회사들이 에너지 공급을 회피하고 보조서비스 수입을 과도하게 추구하고자 하는 교차보조유인과 함께 생산측면의 비효율성을 초래한다. 반대로 계통운용자가 보조서비스 비용을 과소하게 보상할 경우, 발전회사들은 보조서비스를 과소 공급함으로써 전력수요의 변동성이 고스란히 전력요금의 변동성으로 전이되고 이는 위험회피적인 소비자의 후생을 감소시키게 된다. 또한 계통안정 및 품질유지의 책임을 지고 있는 계통운용자도 여유 있는 서비스 용량과 충분한 보상금액을 확보하려는 유인에 따라서만 움직이므로 생산효율성 유인이 약해진다. 전력시장 민영화에 있어서 우리나라의 벤치마크인 호주와 뉴질랜드와 보조서비스운영 체제를 살펴봄으로써 그들은 어떻게 도덕적 헤이의 유인을 줄이고자 하였는지를 설명한다. 본 논문은 보조서비스의 필요성을 유발한 원인자에게 보조서비스 필요비용을 할당하는 것이 바람직하다는 시사점을 갖는다. The purpose of this paper is to study the efficient cost-sharing mechanism for system operating ancillary services in the electricity industry. We claim that the current proposal for Korea electricity privatization is extremely vulnerable to moral hazard on the part of generating companies and the resulting production inefficiencies. The current proposal namely the cost-sharing mechanism for system operating ancillary services. mostly benchmarks those of Australia and New Zealand except one important respect. We investigate how Australia and New Zealand designed their cost-sharing mechanism to minimize moral hazard and production inefficiencies. The policy implication is that, in order to maximize the economic efficiency, whoever causes the ancillary service must incur or share its Cost.

Trends in Inequality in Cigarette Smoking Prevalence by Income According to Recent Anti-smoking Policies in Korea: Use of Three National Surveys

Chang, Youngs,Cho, Sanghyun,Kim, Ikhan,Bahk, Jinwook,Khang, Young-Ho The Korean Society for Preventive Medicine 2018 예방의학회지 Vol.51 No.6

Objectives: This study examined trends in inequality in cigarette smoking prevalence by income according to recent anti-smoking policies in Korea. Methods: The data used in this study were drawn from three nationally representative surveys, the Korea National Health and Nutrition Examination Survey, the Korea Community Health Survey, and the Social Survey of Statistics Korea. We calculated the age-standardized smoking prevalence, the slope index of inequality, and the relative index of inequality by income level as a socioeconomic position indicator. Results: Smoking prevalence among men decreased during the study period, but the downward trend became especially pronounced in 2015, when the tobacco price was substantially increased. Inequalities in cigarette smoking by income were evident in both genders over the study period in all three national surveys examined. Absolute inequality tended to decrease between 2014 and 2015 among men. Absolute and relative inequality by income decreased between 2008 and 2016 in women aged 30-59, except between 2014 and 2015. Conclusions: The recent anti-smoking policies in Korea resulted in a downward trend in smoking prevalence among men, but not in relative inequality, throughout the study period. Absolute inequality decreased over the study period among men aged 30-59. A more aggressive tax policy is warranted to further reduce socioeconomic inequalities in smoking in young adults in Korea.

Cancer Patients’ Utilization of Tertiary Hospitals in Seoul Before and After the Benefit Expansion Policy

조상현,Youngs Chang,Yoon Kim 대한예방의학회 2019 Journal of Preventive Medicine and Public Health Vol.52 No.1

Objectives: The aim of this study was to investigate cancer patients’ utilization of tertiary hospitals in Seoul before and after the benefit expansion policy implemented in 2013. Methods: This was a before-and-after study using claims data of the Korean National Health Insurance Service from 2011 to 2016. The unit of analysis was inpatient episodes, and inpatient episodes involving a malignant neoplasm (International Classification of Diseases, Tenth Revision codes: C00-C97) were included in this study. The total sample (n=5 565 076) was divided into incident cases and prevalent cases according to medical use due to cancer in prior years. The tertiary hospitals in Seoul were divided into two groups (the five largest hospitals and the other tertiary hospitals in Seoul). Results: The proportions of the incident and prevalent episodes occurring in tertiary hospitals in Seoul were 34.9% and 37.2%, respectively, of which more than 70% occurred in the five largest hospitals in Seoul. Utilization of tertiary hospitals in Seoul was higher for inpatient episodes involving cancer surgery, patients with a higher income, patients living in areas close to Seoul, and patients living in areas without a metropolitan city. The utilization of the five largest hospitals increased by 2 percentage points after the policy went into effect. Conclusions: The utilization of tertiary hospitals in Seoul was concentrated among the five largest hospitals. Future research is necessary to identify the consequences of this utilization pattern.