Dynamic Analysis of the Effect of Network Externality in Vertically Differentiated Market Hyung-Rae Cho․Minho Rhee † Dept. of Industrial Systems Engineering/ERI, Gyeongsang National University

조형래(Hyung-Rae Cho):이민호(Minho Rhee) 한국산업경영시스템학회 2019 한국산업경영시스템학회지 Vol.42 No.2

Network externalities are essentially dynamic in that the value consumers feel about a product is affected by the size of the existing customer base that uses that product. However, existing studies on network externalities analyzed the effects of network externalities in a static way, not dynamic. In this study, unlike previous studies, the impact of network externalities on price competition in a vertically differentiated market is dynamically analyzed. To this end, a two-period duopoly game model was used to reflect the dynamic aspects of network externalities. Based on the game model, the Nash equilibria for price, sales volume, and revenue were derived and numerically analyzed. The results can be summarized as follows. First, if high-end product has strong market power, the high-end product vendor takes almost all benefits of the network externality. Second, when high-end product has strong market power, the low-end product will take over most of the initial sales volume increase. Third, when market power of high-end product is not strong, it can be seen that the effects of network externalities on the high and low-end products are generally proportional to the difference in quality. Lastly, if there exists a strong network externality, it is shown that the presence of low-end product can be more profitable for high-end product vendor. In other words, high-end product vendor has incentive to disclose some technologies for the market entrance of low-end product, even if it has exclusive rights to the technologies. In that case, however, it is shown that the difference in quality should be maintained significantly.

『소년』의 과학

조형래 ( Hyung Rae Cho ) 국제한국문학문화학회 2009 사이 Vol.6 No.-

개항 이후 서구의 발달된 과학·기술 지식이 조선 내부에 대대적으로 유입되었지만 과학이라는 개념의 정립 및 그 실천과 관련하여 중대한 전환점이 되었던 것은 특히 1900년대 초반이었다. 특히 「소년」은 `과학`을 당시의 중요한 학지(學知)로서 취급하고 있었던 유력한 잡지 중 하나였다. 이것은 서구 사회의 고유한 전통과 문화를 반영하고 있는 특수한 학제이자 실천으로서의 사이언스의 번역어로서 카가쿠(科學)라는 말이 일본에 정착되고, 일본의 대학제도 내부에서 과학의 제반 학과가 설치되고 있었던 상황과 무관하지 않았다. 『소년』에서 주로 `이과`로 나타나고 있는 과학이란 무엇보다도 실험이라는 고유한 실천 및 진리생산 및 사실재현을 위한 정교한 글쓰기의 형식을 도입·정립했다고 할 수 있다. 그것은 당대의 조선인들로 하여금 자연과 세계의 객관적인 인식을 가능하도록 하는 기준을 제공했다. 뿐만 아니라 그것은 생물의 하위범주로서 인간을 자연 내부에 정위하는, 인간정신의 보편화에 관한 인식론적 전회와 관련되어 있다. 어떤 의미에서 과학이란 정의 만족과 관련된 1910년대 조선의 문학론의 탄생과 전혀 무관하지 않은 담론이었다. Since 1876, it had been an extensive flux of scientific and technical knowledge from the West into Cho-sun. But the important times for the establishment and revolution on that concepts in Korea was the early of 1900`s. Especially a word `과학` was treated as modern scholarship in So-nyun(the Young). This is a translation of very science that is the principle and practice of study represented historical traditions, experiences and cultures of the west And it was translated as Japanese Kagaku(科學) that introduced as study and education system into the society at that time. These were related with the beginning of modern science in Korea and with So-nyun first of all. In this children`s magazine it was mainly called a word `이과` that could make a particular practice of an experiment and a form of ecriture for production of truth and representation of experience. Also it offered to Korean some standardization for objective recognition of nature and world. Futhermore it considered a man to a part of nature, and then universalized human mental. This caused very important epistemological conversion about understanding nature and world. In a manner of speaking, science as episteme had concerned with discourses on the birth of literature as the satisfaction of sense in 1910`s Korea.

동역학적 특성을 고려한 스튜어트형 매니퓰레이터의 설계

조형래,홍금식 釜山大學校生産技術硏究所 1996 生産技術硏究所論文集 Vol.51 No.-

본 논문은 병렬형 매니퓰에이터의 구동부에 입력되는 힘과 상판으로 출력되는 힘과 모우멘트의 전달특성을 연구하였다. 이러한 전달특성을 연구하기 위하여 상관좌표계의 원점을 기준으로한 힘과 모우멘트 벡터로 구성되는 행렬을 힘과 모우멘트의 2부분으로 분리한 후 특이값 분해를 통하여 힘 및 모우멘트의 조종성능, 민감도, 방향성 등을 해석하였다. 이렇게 해석된 결과들은 병렬형 매니퓰레이터의 설계변수의 한 지침으로 사용되어질 수 있다. This paper presents how the input forces through the prismatic joints of the Stewart platform manipulator are transmitted to the upper plate. The matrix containing unit vectors along the legs and moment vectors about the origin of platform based on the plucker coordinate system is splitted into two parts to consider the force and moment transmissions, respectively. Manipulability and sensitivity were investigated in accordance with the changes of radius of platform and angle between legs. Acquired results could be useful in-determining design parameters like radius of platform, angle between joints in the base and platform, etc.

VDT 作業者의 自覺症狀에 관한 調査硏究

池亨來,曺永釵,李棟培 忠南大學校 環境問題硏究所 1991 環境硏究 Vol.9 No.-

The aims of this study were to examine the relevancy between the VDT(visuall display terminal) workers subjective symptoms which are increasing rapidly and to know the factors which exert an influence on the complaints of subjective symptoms perception. A questionnaire survey was conducted among 464 VDT workers and 312 control group workers from December 1, 1990 to February 28, 1991. The total 26 subjective symptoms were answered by NOTHING, SOMETIMES, and ALWAYS and groupied largely into eye symptom(8 items), musculoskeletal symptom(7 items) and psychoneurotic symptom(11 items). To analyze the influences of factors related to the subjective symptom, the auther allocated score 0 for the answer "nothing", score 1 for the answer "sometimes", and score 2 for the answer "always", Following conclusions were obtained. The proportion of complaints of subjective symptoms in VDT group was 62.7%, but that was 45.6% in control group. The major symptoms, complained, were eye strain(95.9%), fatigue(93.8%), shoulders or neck stiffness (89.0%), conjunctival injection(72.6%), low back pain(72.0%), sore eye(68.8%), pain in arms(63.1%) and blurring of distance(58.4%) in that order. The main score of psychoneurotic symptom was highest in both sexes. That was 6.49 in males and 7.87 in females. Only the mean score of musculoskeletal symptoms were highest in female group. The mean score of eye symptom was highet in over 40 age group but that of musculoskeletal symptoms was highest in the 30's age groups. The mean score of eye strain was highest among personal computer worker, but that of musculoskeletal symptom were highest among computer trade worker in the bank. The factors influenced to the amblyopia were work career, type of using VDT, hours of VDT working per a day, and using of a protective lenses. The mean scores of symptoms became increased with the average working hours per a day. Total years of VDT working and the mean score of subjective syptom showed positive correlation but age showed negative correlation with mean scores of subjective symptoms.

3차 PLL SYSTEM에서의 flicker noise 분석

김형도,김경복,조형래 韓國海洋大學校電波通信硏究所 1999 電波通信硏究所論文集 Vol.1 No.-

본 논문에서는 PLL 시스템의 보다 실제적인 모델인 3차 시스템을 통하여 저주파 대역에서 문제가 되는 flicker noise가 어떠한 양상을 나타내는가를 알아보려 한다. 3차에서 해석의 복잡성으로 그 수학적 분석이 난해하지만 최적화 된 2차 필터를 통한 pseudo-damping factor의 도입으로 전체적인 flicker variance의 해석이 용이하도록 시도하였다. 3차에서의 flicker variance의 수식적인 유도를 보이고 이를 2차 시스템에서 발생되는 flicker noise에 대한 variance와 비교하려 한다. In this paper, using third-order system of the PLL we analyze the aspect of flicker noise appearing troubles in the low frequency band. Since it is difficult to analyze mathematically flicker noise in the third-order system of the PLL, introducing the concept of pseudo-damping factor using the optimized second-filter makes an ease of the access of the flicker-noise variance. We'll show a numerical formula of flicker variance in the third-order system of the PLL which is compared with that of 1/f noise variance in the second-order system of the PLL.

초고속 전송에 대한 Ultrashort Laser Pulse의 새로운 스펙트럼 분석

전진성,조형래,오용선 韓國海洋大學校電波通信硏究所 1999 電波通信硏究所論文集 Vol.1 No.-

본 논문에서는, Class-2 PRS 모델의 전달함수인 Raised-Cosine 펄스를 이용하여 극초단 레이저펄스의 전송특성을 분석하였다. 이는 Class-1 PRS 모델에서와 같이 부분응답시스템의 수정된 모델로부터 얻어지는 고차원펄스를 이용하여 그 차수의 증가에 따라 FWHM폭이 현저히 감소하여 분석하고자 하는 극초단펄스의 형태에 근접하는 펄스를 제시하였으며, 그 스펙트럼과 전송대역폭도 차수에 따라 일률적으로 유도되므로 Gaussian, Sech형태의 펄스 같은 고전적인 방법과는 달리 광범위하고 정확한 전송특성을 분석하는데 매우 유용함을 밝혔다. 먼저, 부분응답시스템의 일반적인 모델을 수정하여 어떤 형태의 고차원펄스도 적용할 수 있는 새로운 방법을 제안하였다. 그리고 제안된 모델을 이용하여 어떠한 형태의 FWHM을 가지는 극초단펄스의 전송에 대한 새로운 분석 방법을 제안하였다 제안된 방법을 사용하여, 설정 펄스 폭을 τ=1(㎰)으로 설정, 고차원펄스의 차수 n=1~100에서 얻어지는 FWHM 1(㎰)~100(fs)의 극초단펄스의 스펙트럼을 제시하였고, Class-2 PRS 모델의 FWHM 폭이 Class-1 PRS 모델보다는 차수 n에 따라서 약 50~100(fs)정도 좁은 FWHM 폭을 가짐을 밝혔다. 이에 대한 전송특성은 레이저펄스의 보편적인 신호방식인 Unipolar 체계로 설정하여, 가능한 펄스간격에 따른 PSD를 유도하여 제시하였다. 이러한 결과들은 고전적인 실험 방법과는 일치함을 물론 미래 극초단펄스 연구에 대한 혁신적인 방법으로 사용될 수 있을 것이다. In this paper, we analyze transmission characteristics of ultrashort laser pulses using the property of Raised-cosine pulse which are systematically obtained following Class-2 PRS model. The high-order pulses are easily derived from a modified PRS system model as Class-1 PRS model. This may be based on the fact that the spectra and bandwidths of the high-order pulses are beautifully related to their orders. And we make clear they are very useful to cover wider area and more accurate transmission characteristics of ultrashort pulses than Gaussian or Sech pulse approximations used conventionally. First modifying the generalized PRS system model, we propose a new model for deriving any type of high-order pulse. And we offer a novel analysis method of ultrashort pulse transmission which has any shape and FWHM, using the proposed model. In addition, by fixing the pulse range τ=1(㎰) and varying the order of the pulse from n=1 to n=100, we obtain spectra of ultrashort pulses with 1(㎰)~100(fs) FWHM's, and width of FWHM in the Class-2 PRS model 50~100(fs) smaller than Class-1 PRS model. As a one-step further, we derive PSD's of their pulse trains when they are applied to Unipolar signaling scheme. These PSD's are decided in the range of possible pulse intervals. All of these results are not only coincided with some conventional experimental works but also will be applied to any pioneering ultrashort pulse in the future.

기업내에서 부서간 갈등해결을 위한 의사결정조정 메커니즘에 관한 연구 : 웹 DSS 접근방법을 중심으로 Emphasis on Web-DSS Approach

이건창,조형래 한국경영과학회 2001 韓國經營科學會誌 Vol.26 No.1

As the advent of the Internet, most of the modern firms are now forced to use the Internet as one of telecommunication tools for daily activities. Especially, as the decision units and/or makers in a firm become geographically dispersed due to the globalization trend, the need for integrating them effectively on the Internet is getting attention from researchers and practitioners much more than ever. In literature, this kind of need has been specially conspicuous in the need for coordinating production and marketing activities which are known as one of the typically conflicting with each other in terms of purposes. Lee and Lee(1999) has proposed an interesting coordination environment for production and marketing, named PROMISE. This paper is aimed at improving the coordination algorithm utilized in PROMISE and accordingly proposing a web-driven DSS for the purpose of transforming Promise into a web-based decision support platform for production and marketing coordination.

Web 인지도를 반영한 전자상거래 마케팅 채널 경쟁에 관한 연구

차춘남,조형래 한국경영과학회 2000 經營 科學 Vol.17 No.3

The proliferation of electronic commerce(EC) has led manufacturers to consider internet based marketing as a salient candidate for strategic diversification of marketing channel. In this case, each manufacturer can build its own Web store or rent an existing special EC store. Such decision making of 'build' or 'rent' can be analyzed by a game model which derives the Nash solutions for price and profit considering degree of competition with other competitive manufacturers. In this paper, to overcome the drawbacks of the traditional linear demand function, we first propose a new linear demand function which incorporates not only the price difference between competitive products but the awareness of Web stores perceived by the consumers, then design the game models to analyze the characteristics of three typical types of marketing channel in duopoly market. Based on the Nash solutions of the game models, we analyzed the effect of the degree of competition and Web awareness in selecting the optimal marketing channel.

계층화된 퍼지인식도(Fuzzy Cognitive Map)를 이용한 추론메카니즘에 관한 연구

이건창,조형래 한국경영과학회 1998 한국경영과학회지 Vol.23 No.4

본 논문에서는 FCM을 이용하여 의사결정의 질을 높일 수 있는 추론방법을 제시한다. 이를 위하여 FCM의 추론의 질을 저하시키는 문제중의 하나인 동기화 문제(synchronization problem)를 설명하고, 이를 해결하기 위한 방안으로서 FCM 계층화(levelization) 알고리즘을 제시한다. 본 논문에서 제안된 계층화된 FCM을 이용한 추론절차를 제시하고, 그 활용예를 설명한다.

구매의사결정 지원을 위한 실시간 가격비교 Agent 개발

권효석,류정섭,조형래 경상대학교 생산기술연구소 2001 工學硏究院論文集 Vol.1 No.-

The proliferation of the internet and related applications has made users struggle with information overload. It means users must spend more time to find and gather necessary information they want. The agent technique is advocated by many researchers as an alternative to overcome the difficulty, which resulted in the practical use of the agent technique in Electronic Commerce more common. In this paper, we propose a realtime price comparison agent which compares the prices and services among online stores in realtime without users' intervention. The proposed agent differs from the existing ones in that (1) it does not incorporate a pre-installed price database, (2) it automatically monitors users' current status without any input from the users.