• 제목/요약/키워드: context problem

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수요 불확실성과 공급 불확실성의 상호 작용이 공급 사슬 비용에 미치는 효과에 대한 연구 (Study on the Effects of the Interactions between Demand and Supply Uncertainties on Supply Chain Costs)

  • 박상욱;김수욱
    • 한국경영과학회지
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    • 제30권3호
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    • pp.81-93
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    • 2005
  • This paper models supply chain uncertainties in the dynamic Newsboy Problem context. The system consists of one supplier and one retailer who place an order to the supplier every period. Demand uncertainty is modeled as stochastic period demand, and supply uncertainty as the uncertainty in quantities delivered by the supplier. The supplier delivers exactly the amount ordered by the retailer with probability of $\beta$ and the amount minus K with probability of $(1-\beta)$ We formulate the problem as a dynamic programming problem and derive the first-order optimality condition. Through a numerical study, we measure the extent to which the cost decrease due to the reduction in supply uncertainty depends on the level of demand uncertainty. One of the most important findings In this paper is that this cost decrease is relatively small if demand uncertainty is kept high, and vice versa. We also backup this numerical result by analyzing the distribution of ending Inventory under the supply and demand uncertainties.

대학생의 운동학 그래프 작성에 대한 역학 개념의 효과 (The Effect of Force and Motion Conceptions into the Kinematics Graph Construction)

  • 권성기
    • 한국과학교육학회지
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    • 제17권4호
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    • pp.383-393
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    • 1997
  • In order to study the effect of student's conceptions about force and motion into the graph construction in kinematics in college physics course, the tasks of constructing the qualitative graph in the similar problem context used in force conception was asked to the first 74 and third 97 student teacher in teachers' university. The frequencies analysis showed that student teachers had the naive conceptions that the throwing force was still acted to a upwarding ball. They also had the popular Aristotelian views about motion. These naive conceptions coexisted with the scientific conception about gravitational force. In a simple pendulum problem no one had the correct acceleration concepts which varies the direction in swing. This result suggest that student teacher had more difficulties in a acceleration problem than in a velocity problem In v-t and a-t graph construction tasks, the number of categories of a-t graphs were more than that of v-t graphs. There were many graph errors in a sign of velocity and acceleration. The acceleration conceptions without the relations of changes in velocity made the kinematics graphs more various shapes. The force and motion conceptions influenced the ability to construct the kinematics graphs.

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소비자 네트워크의 변화 관리 문제 : 최소지배집합 역 문제의 계산 복잡성 증명 (The Challenge of Managing Customer Networks under Change : Proving the Complexity of the Inverse Dominating Set Problem)

  • 정예림;박선주;정승화
    • 한국경영과학회지
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    • 제39권2호
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    • pp.131-140
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    • 2014
  • Customer networks go through constant changes. They may expand or shrink once they are formed. In dynamic environments, it is a critical corporate challenge to identify and manage influential customer groups in a cost effective way. In this context, we apply inverse optimization theory to suggest an efficient method to manage customer networks. In this paper, we assume that there exists a subset of nodes that might have a large effect on the network and that the network can be modified via some strategic actions. Rather than making efforts to find influential nodes whenever the network changes, we focus on a subset of selective nodes and perturb as little as possible the interaction between nodes in order to make the selected nodes influential in the given network. We define the following problem based on the inverse optimization. Given a graph and a prescribed node subset, the objective is to modify the structure of the given graph so that the fixed subset of nodes becomes a minimum dominating set in the modified graph and the cost for modification is minimum under a fixed norm. We call this problem the inverse dominating set problem and investigate its computational complexity.

문제 만들기를 통해 알아본 교사의 내용지식 사용에 대한 결정과 수행 - 미국 사례를 중심으로 (Teachers' Decision and Enactment of Their Content Knowledge Assessed Through Problem Posing - A U.S. Case)

  • 노지화
    • 한국수학교육학회지시리즈E:수학교육논문집
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    • 제31권2호
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    • pp.153-166
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    • 2017
  • 본 연구에서는 예비교사가 문제 만들기 과제를 위해 분수곱셈지식을 사용하는 과정에서 드러나는 이해의 정도와 유형을 미국사례를 중심으로 조사하였다. 이를 위하여, 미국 대학 교사교육과정의 입문단계와 종료단계에 있는 총 164명의 예비초등교사를 대상으로 분수곱셈에 대한 문장제 문제를 작성하게 하고, 이를 수학적 정교성과 작성한 문제에 사용한 분수곱셈의 의미의 유형으로 분석하였다. 분석결과는 교육과정 입문단계와 종료단계의 예비교사 그룹 간의 차이점, 각 그룹, 그리고 전체적인 경향에 대해 기술하였고, 분수곱셈 지도와 교사교육에 대한 시사점을 제공하였다.

이슈 네트워크를 활용한 사용자 조사 방법론: 자동차 내비게이션 디자인을 중심으로 (The Issue-network: A Study of New User Research Method in the Context of a Car Navigation Design)

  • 김동환;이동민;하세용;이준환
    • 한국멀티미디어학회논문지
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    • 제22권4호
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    • pp.502-514
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    • 2019
  • Existing user research methods are subject to a variety of research conditions such as the amount and variety of data collected and the expertise of the facilitator of a group research session. In this study, we propose a new user research methodology using an 'Issue-Network' system, which is developed based on the theory and methods of social network analysis. The Issue-Network is designed to define problem spaces from the issues raised by users in a group research session in a form of an interactive network graph. The system helps to break out of ordinary perspectives of looking into problem spaces by enabling an alternative and more creative way to connect issues in the network. In this study, we took a case study of generating the Issue-Network on behalf of the problems raised by users in various driving-related situations. We were able to draw three navigation usage scenarios that cover relatively important problem spaces: safety and being ready for the unexpected, smart navigation and notifications, making use of the spare time. In the future, the Issue-Network system is expected to be used as a tool to identify problems and derive solutions in group research sessions involving a large number of users.

디자인의 형태와 기능에 관한 연구 (Essay on Form and Function Design)

  • 이재국
    • 디자인학연구
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    • 제2권1호
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    • pp.63-97
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    • 1989
  • There is nothing more important than the form and function in design, because every design product can be done on the basis of them. Form and Function are already existed before the word of design has been appeared and all the natural and man-made things' basic organization is based on their organic relations. The organic relations is the source of vitality which identifies the subsistance of all the objects and the evolution of living creatures has been changed their appearances by the natural law and order. Design is no exception. Design is a man-made organic thing which is developed its own way according to the purposed aim and given situations. If so, what is the ultimate goal of design. It is without saying that the goal is to make every effort to contribute to the -human beings most desirable life by the designer who is devoting himself to their convenience and well-being. Therefore, the designer can be called the man of rich life practitioner. This word implies a lot of meanings since the essence of design is improving the guality of life by the man-made things which are created by the designer. Also, the things are existed through the relations between form and function, and the things can keep their value when they are answered to the right purpose. In design, thus, it is to be a main concern how to create valuable things and to use them in the right way, and the subject of study is focused on the designer's outlook of value and uk relations between form and function. Christopher Alexander mentioned the importance of form as follows. The ultimate object of design is form. Every design problem begins with an effort to achieve fittness between the form and its context. The form is the solution to the problem: the context defmes the problem. In other words, when we speak of design, the real object of discussion is not form alone, but the ensemble comprising the form and its context. Good fit is a desirable property of this ensemble which relates to some particular division of the ensemble into form and context. Max Bill mainatined how important form is in design. Form represents a self-contained concept, and its embodiment in an object results in that object becoming a work of art. Futhermore, this explains why we use form so freguently in a comparative sense for determining whether one thing is less or more beautiful than another, and why the ideal of absolute beauty is always the standard by which we appraise form, and through form, art itself. Hence form has became synonymous with beauty. On the other hand, Laszlo Moholy-Nagy stated the importance of function as follows. Function means the task an object is designed to fulfill the task instrument is shaping the form. Unfortunately, this principle was not appreciated at the same time but through the endeavors of Frank Lloyd Wright and of the Bauhaus group and its many collegues in Europe, the idea of functionalism became the keynote of the twenites. Functionalism soon became a cheap slogan, however, and its original meaning blurred. It is neccessary to reexamine it in the light of present circumstances. Charles William Eliot expressed his idea on the relations between function and beauty. Beauty often results chiefly from fittness: indeed it is easy to manitain that nothing is fair except what is fit its uses or functions. If the function of the product of a machine be useful and valuable, an the machine be eminently fit for its function, it conspicuously has the beauty of fittness. A locomotive or a steamship has the same sort of beauty, derived from the supreme fittness for its function. As functions vary, so will those beauty..vary. However, it is impossible to study form and function in separate beings. Function can't be existed without form, and without function, form is nothing. In other words, form is a function's container, and function is content in form. It can be said that, therefore, the form and function are indispensable and commensal individuals which have coetemal relations. From the different point of view, sometimes, one is more emphasized than the other, but in this case, the logic is only accepted on the assumption of recognizing the importance of the other's entity. The fact can be proved what Frank Hoyd wright said that form and function are one. In spite of that, the form and function should be considered as independent indivisuals, because they are too important to be treated just as the simple single one. Form and function have flexible properties to the context. In other words, the context plays a role as the barometer to define the form and function, also which implies every meaning of surroun'||'&'||'not;dings. Thus, design is formed under the influence of situations. Situations are dynamic, like the design process itself, in which fixed focus can be cripping. Moreover, situations control over making the good design. Judging from the respect, I defined the good design in my thesis An Analytic Research on Desigh Ethic, "good design is to solve the problem by the most proper way in the situations." Situations are changeable, and so is design. There is no progress without change, but change is not neccessarily progress. It is highly desirable that there changes be beneficial to mankind. Our main problem is to be able to discriminate between that which should be discarded and that which should be kept, built upon, and improved. Form and Function are no exception. The practical function gives birth to the inevitable form and the $$\mu$ti-classified function is delivered to the varieties of form. All of these are depended upon changeable situations. That is precisely the situations of "situation de'||'&'||'not;sign", the concept of moving from the design of things to the design of the circumstances in which things are used. From this point of view, the core of form and function is depended upon how the designer can manage it efficiently in given situations. That is to say that the creativity designer plays an important role to fulfill the purpose. Generally speaking, creativity is the organization of a concept in response to a human need-a solution that is both satisfying and innovative. In order to meet human needs, creative design activities require a special intuitive insight which is set into motion by purposeful imagination. Therefore, creativity is the most essential quality of every designer. In addition, designers share with other creative people a compulsive ingenuity and a passion for imaginative solutions which will meet their criteria for excellence. Ultimately, it is said that the form and function is the matter which belongs to the desire of creative designers who constantly try to bring new thing into being to create new things. In accordance with that the main puppose of this thesis is to catch every meaning of the form and function and to close analyze their relations for the promotion of understanding and devising practical application to gradual progression in design. The thesis is composed of four parts: Introduction, Form, Function and Conclusion. Introduction, the purpose and background of the research are presented. In Chapter I, orgin of form, perception of form, and classification of form are studied. In Chapter II, generation of function, development of function, and diversification of function are considered. Conclusion, some concluding words are mentioned.ioned.

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An Integrated Approach to Teaching and Learning College Mathematics

  • Ahuja, Om P.;Jahangiri, Jay M.
    • 한국수학교육학회지시리즈D:수학교육연구
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    • 제7권1호
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    • pp.11-24
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    • 2003
  • The key features of our integrated approach to teaching and loaming college mathematics include interactive and discussion-based teaching, small group work, computer as a tool, problem solving approach, open approach, mathematics in context, emphasis on mathematical thinking and creativity, and writing/communicating about mathematics. In this paper we report a few examples to illustrate the type of problems we use in our integrated approach.

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클러스터 중심 결정 방법에 따른 문서 클러스터링 성능 분석 (Analysis of Document Clustering Varing Cluster Centroid Decisions)

  • 오형진;변동률;이신원;박순철;정성종;안동언
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2002년도 하계종합학술대회 논문집(3)
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    • pp.99-102
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    • 2002
  • K-means clustering algorithm is a very popular clustering technique, which is used in the field of information retrieval. In this paper, We deal with the problem of K-means Algorithm from the view of creating the centroids and suggest a method reflecting document feature and considering the context of each document to determine the new centroids during the process of forming new centroids. For experiment, We used the automatic document summarizer to summarize the Reuter21578 newslire test dataset and achieved 20% improved results to the recall metrics.

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Esophageal perforation in children: etiology and management, with special reference to endoscopic esophageal perforation

  • Govindarajan, Krishna Kumar
    • Clinical and Experimental Pediatrics
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    • 제61권6호
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    • pp.175-179
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    • 2018
  • Perforation of the esophagus is an uncommon problem with significant morbidity and mortality. In children undergoing endoscopy, the risk of perforation is higher when interventional endoscopy is performed. The clinical features depend upon the site of esophageal perforation. Opinions vary regarding the optimal treatment protocol, and the role of conservative management in this context is not well established. Esophageal perforation that occurs as a consequence of endoscopy in children requires careful evaluation and management, as outlined in this article.

Empirical Choice of the Shape Parameter for Robust Support Vector Machines

  • Pak, Ro-Jin
    • Communications for Statistical Applications and Methods
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    • 제15권4호
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    • pp.543-549
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    • 2008
  • Inspired by using a robust loss function in the support vector machine regression to control training error and the idea of robust template matching with M-estimator, Chen (2004) applies M-estimator techniques to gaussian radial basis functions and form a new class of robust kernels for the support vector machines. We are specially interested in the shape of the Huber's M-estimator in this context and propose a way to find the shape parameter of the Huber's M-estimating function. For simplicity, only the two-class classification problem is considered.