• 한국수학교육학회지시리즈A:수학교육
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• 제48권4호
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• pp.419-442
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• 2009

This study was to find the difficulties students faced in their mathematical learning and to identify the instructional dimensions a teacher provided for the students from multi-cultural background. Since the study was focused on the process of students' learning, the qualitative method was chosen through clinical interviews with 2 students in a total of 11 units which played a role of compensating their learning of mathematics as an extra curriculum. The students solved the computational problems relying on formal procedure without understanding of concepts and principles and solved the word problems based on own interpretation of certain words without semantic comprehension out of math sentences. As the instructional dimensions of teaching mathematics, tasks, a tool and classroom norm were found in the activities they performed. For the tasks, situated tasks, challenging tasks, tasks with lack of conditions, and open-ended exploratory tasks were used. As the tool, pictorial representations were very useful to describe their ideas. Finally, as the classroom norm, consider equity for everyone, and cooperate and encourage each other were found.

• 경영과학
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• 제18권1호
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• pp.55-68
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• 2001

A virtual shopping mall is like a real-world mall, supports electronic shopping by selling products or services through Interne. Although increasing numbers of products are being marketed on the Web, little efforts has been spent on evaluating what mall is more suitable for marketing electronically and for protecting consumers. Evaluation of virtual shopping malls is regarded as a major task in business-to-consumer electronic commerce. This paper considers the Analytic Hierarchy Process(AHP) method in the evaluation of virtual shopping malls and provides its applications. The AHP is a systematic procedure for representing the elements of any problem, hierarchically. A series of pairwise comparison judgments is performed to express the relative strength or intensity of impact of the elements in the hierarchy. The AHP model hierarchy consists of the four following levels: decision maker, main criteria, sub-criteria, and virtual shopping malls. the main criteria include the state of physical firms, representation of information on the virtual shopping malls, product or service, convenience for shopping, consumer protection, and consumer service. The total number of sub-criteria in the third level is twenty-nine. All decision makers selected belong to virtual shopping mall enterprises, or universities. As a case study, we show the synthesized priority of the five virtual shopping malls that have acquired an E-Trust mark. Finally a sensitivity analysis shows how well each virtual shopping mall performs on each criterion by increasing or decreasing the importance of the main criteria.

• The Korean Journal of Pain
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• 제10권1호
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• pp.117-120
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• 1997

Cancer is a devastating disease, and the treatment of related pain is an extremely challenging task. Providing adequate analgesia while avoiding unnecessary drug effects often requires a polypharmacologic approach in cancer pain management. A 36-year old woman with breast cancer metastatic to the axial skeleton and bilateral hip joints was admitted to hemato-oncology service with complaints of intractable abdominal and hip pain. Despite rapidly increasing doses of intravenous morphine up to 350 mg per day; transdermal fentanyl; midazolam; ketorolac; lorazepam; dexamethasone, the patient continued to describe her pain as 10 of 10, refusing all surgical/diagnostic interventions not directly related to pain control. She did, however, consent to lumbar epidural catheter placement. The patient was sedated with titrating doses of propofol to assist with positioning. Even though the procedure was not successful due to significant thoracolumbar scoliosis, the patient admitted feeling better than she has in months during attempted placement. After continuous infusion of propofol was initiated at subhypnotic dose, the patient's analgesic demand was drastically reduced and described her pain as "1 to 3" of "10". Approximately 96 hours after the propofol infusion was started, the patient expired comfortably. There had been no change in her medical regimen during fecal 48 hours. In the case described, propofol was extremely advantageous as an adjuvant in the management of cancer related pain.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1994년도 가을 학술발표회 논문집
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• pp.267-272
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• 1994

This work presents a method of optimum design for reinforced concrete building frames with rectangular cross sections. The optimization techniques used is based on the principle of divided parameters. The design variable parameters are divided into two groups, external and internal, and the optimization is also divided into external and internal procedure. This principle overcomes difficulties arising from the presence of two materials in one element, the property peculiar to reinforced concrete. Several search algorithms are tested to verify their accuracy for the external optimization. Among them pattern search algorithms has been found consistent. This work proposes a new method, modified pattern search, and a number of sample problems prove its accuracy and usefulness. Exhaustive search for all local minima in the design spaces for two sample problems has been carried out to understand the nature of the problem. The number of local minima identified is quite more than expected and it has become understood that the researcher's task in this field is to find a better local minimum if not global. The designs produced by the method preposed have been found better than those from other method, and they are in full accord with ACI Building Code Requirments(ACI 318-89).

• Journal of Electrical Engineering and Technology
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• 제12권6호
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• pp.2166-2176
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• 2017

Electricity price prediction plays a crucial part in making the schedule and managing the risk to the competitive electricity market participants. However, it is a difficult and challenging task owing to the characteristics of the nonlinearity, non-stationarity and uncertainty of the price series. This study proposes a hybrid improved strategy which incorporates data preprocessor components and a forecasting engine component to enhance the forecasting accuracy of the electricity price. In the developed forecasting procedure, the Seasonal Adjustment (SA) method and the Ensemble Empirical Mode Decomposition (EEMD) technique are synthesized as the data preprocessing component; the Coupled Simulated Annealing (CSA) optimization method and the Least Square Support Vector Regression (LSSVR) algorithm construct the prediction engine. The proposed hybrid approach is verified with electricity price data sampled from the power market of New South Wales in Australia. The simulation outcome manifests that the proposed hybrid approach obtains the observable improvement in the forecasting accuracy compared with other approaches, which suggests that the proposed combinational approach occupies preferable predication ability and enough precision.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2004년도 Proceedings of the 4th Korea-China Joint Workshop on Nuclear Waste Management
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• pp.205-219
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• 2004

The remote operation of the Advanced Spent Fuel Conditioning Process (ACP) is analyzed by using the 3D graphic simulation tools. The ACP equipment operates in intense radiation fields as well as in a high temperature. Thus, the equipment should be designed in consideration of the remote handling and maintenance. As well as suitable remote handling and maintenance technology needs to be developed along with the design of the process concepts. To develop such remote operation technology, we developed the graphic simulator which provides the capability of verifying the remote operability of the ACP without fabrication of the process equipment. In other words, by applying virtual reality to the remote maintenance operation, a remote operation task can be simulated in the graphic simulator, not in the real environment. The graphic simulator will substantially reduce the cost of the development of the remote handling and maintenance procedure as well as the process equipment, while at the same time developing a remote maintenance concept that is more reliable, easier to implement, and easier to understand.

• Geomechanics and Engineering
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• 제13권2호
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• pp.237-254
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• 2017

Estimation of slope stability is a very important task in geotechnical engineering. However, its estimation using conventional and soft computing methods has several drawbacks. Use of conventional limit equilibrium methods for the evaluation of slope stability is very tedious and time consuming, while the use of soft computing approaches like Artificial Neural Networks and Fuzzy Logic are black box approaches. Multiple Regression (MR) analysis provides an alternative to conventional and soft computing methods, for the evaluation of slope stability. MR models provide a simplified equation, which can be used to calculate critical factor of safety of slopes without adopting any iterative procedure, thereby reducing the time and complexity involved in the evaluation of slope stability. In the present study, a multiple regression model has been developed and tested its accuracy in the estimation of slope stability using real field data. Here, two separate multiple regression models have been developed for dry and wet slopes. Further, the accuracy of these developed models have been compared and validated with respect to conventional limit equilibrium methods in terms of Mean Square Error (MSE) & Coefficient of determination ($R^2$). As the developed MR models here are not based on any region specific data and covers wide range of parametric variations, they can be directly applied to any real slopes.

• 한국멀티미디어학회논문지
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• 제3권1호
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• pp.77-90
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• 2000

실시간 검증은 명세와 요구사항과의 논리적 정확성 뿐만 아니라 시간적 정확성을 확인하는 일련의 과정이다. 하지만 시간의 무한성에 의해 시스템 상태가 무한히 증가할 수 있는 상태 폭발 문제가 검증과정에서 중요한 문제점이 되고 있다. 본 논문에서는 형식 검증에 기반을 두며, 시스템의 행위 측면을 시간 오토마타로 기술한 시스템 모델이 Timed mu-calculus로 표현된 시스템의 특성에 만족하는지의 여부를 통해 명세의 완전성을 확인하는 실시간 검증 비법을 기술한다. 이를 위해 초기상태의 논리값에 초점을 두어 검증과정에서 필요로 하는 노드로만 Product Graph를 구성하여 노드 값을 결정해나가는 지역모형검사 기법에 대해 제안한다. 이 방법은 모델의 모든 상태를 조사하지 않으므로 상태 폭발 문제를 최소화 시킬 수 있어 실시간 시스템 검증에 효과적으로 적용이 가능하다.

• 한국도서관정보학회지
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• 제44권2호
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• pp.27-50
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• 2013

본 연구의 목적은 학교도서관의 스마트러닝 수업 모형을 정보활용교육 측면에서 개발하는 것이다. 수업 모형은 ADDIE 모형과 ASSURE 모형을 기반으로 학교도서관의 특성에 맞게 도서관의 시설, 자료, 인적자원, 정보문제 해결과정, 협동수업 및 블렌디드 학습, 스마트 디바이스의 이용 등이 고려되었다. 수업 모형은 "학습목표 설정${\rightarrow}$학습자 분석${\rightarrow}$학습환경 분석${\rightarrow}$학습과제 분석${\rightarrow}$교수 전략${\rightarrow}$매체 선정 및 개발${\rightarrow}$수업적용${\rightarrow}$평가"의 순서로 개발하였다. 또한 학교도서관 스마트러닝의 실제적인 상황에 대한 이해를 돕기 위해서 수업 예시를 제시하였다.

• International Journal of Control, Automation, and Systems
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• 제5권5호
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• pp.547-558
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• 2007

This paper proposes a simpler solution to the stabilization problem of a special class of nonlinear underactuated mechanical systems which includes widely studied benchmark systems like Inertia Wheel Pendulum, TORA and Acrobot. Complex internal dynamics and lack of exact feedback linearizibility of these systems makes design of control law a challenging task. Stabilization of these systems has been achieved using Energy Shaping and damping injection and Backstepping technique. Former results in hybrid or switching architectures that make stability analysis complicated whereas use of backstepping some times requires closed form explicit solutions of highly nonlinear equations resulting from partial feedback linearization. It also exhibits the phenomenon of explosions of terms resulting in a highly complicated control law. Exploiting recently introduced Dynamic Surface Control technique and using control Lyapunov function method, a novel nonlinear controller design is presented as a solution to these problems. The stability of the closed loop system is analyzed by exploiting its two-time scale nature and applying concepts from Singular Perturbation Theory. The design procedure is shown to be simpler and more intuitive than existing designs. Design has been applied to important benchmark systems belonging to the class demonstrating controller design simplicity. Advantages over conventional Energy Shaping and Backstepping controllers are analyzed theoretically and performance is verified using numerical simulations.