• Management Science and Financial Engineering
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• v.15 no.2
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• pp.69-100
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• 2009

In this paper, we consider a relatively new two-machine flow shop scheduling problem where the unit time WIP cost increases as a job passes through various stages in the production process, and the objective is to minimize the total WIP (work-in-process) cost. Specifically, we study three special cases of the problem. First, we consider the problem where processing times on machine 1 are identical. Second, the problem with identical processing times on machine 2 is examined. The recognition version of the both problems is unary NP-complete (or NP-complete in strong sense). For each problem, we suggest two simple and intuitive heuristics and find the worst case bound on relative error. Third, we consider the problem where the processing time of a job on each machine is proportional to a base processing time. For this problem, we show that a known heuristic finds an optimal schedule.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.12
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• pp.1262-1268
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• 1991

The electric furnace which has time delay and time varying characteristics cannot be controlled easily. In this paper, a fuzzy controller for a electric furnace is implemented using one chip processor 8751 and IBM PC. The fuzzy controller is implemented in the PC. The One chip processor 8751 can sense the furnace internal temperature and pass it to IBM PC and generate the driving signal for SSR. The membership function of the fuzzy controller is determined by Least Square method. from the experiments, we can show that the fuzzy controller can improve robustness to the load variation. And the settling time is reduce 4500 (sec) to 2500 (sec).

• Journal of the Korean Statistical Society
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• v.28 no.3
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• pp.359-370
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• 1999

We considered a change-point hazard rate model generalizing constant hazard rate model. This type of model is very popular in the sense that the Weibull and exponential distributions formulating survival time data are the special cases of it. Maximum likelihood estimation and the asymptotic properties such as the consistency and its limiting distribution of the change-point estimator were discussed. A parametric bootstrap method for finding confidence intervals of the unknown change-point was also suggested and the proposed method is explained through a practical example.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.47-50
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• 2007

This study attempts to prove a superiority of slide-cover lighting. In order to solve these problems, cover materials with slide-type, blind cover should be prepared to make it easy to replace the light bulbs in a short time and to introduce a sense of decorative taste. Depending on an user's linking, slide-type cover can always change the indoor atmosphere by adjusting the light emitted from the lighting and meeting with the blind unit

• The Pure and Applied Mathematics
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• v.18 no.3
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• pp.231-244
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• 2011

We prove the Hyers-Ulam stability for trigonometric type functional inequalities in restricted domains with time variables. As consequences of the result we obtain asymptotic behaviors of the inequalities and stability of related functional inequalities in almost everywhere sense.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.03a
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• pp.39-42
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• 1998

This paper proposes an adaptive fuzzy control scheme for a class of continuous-time nonlinear dynamic systems for which an explicit linear parameterization of the uncertainty is either unknown or impossible. In order to improve robustness under approximation errors and disturbances the proposed scheme includes deadzone in adaptation laws which varies its size adaptively. The assumption of known bounds on the approximation errors and disturbances is not required since those are estimated using adaptation laws. The overall adaptive scheme is proven to guarantee uniform ultimate boundedness in the Lyapunov sense.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.394-399
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• 1990

We develop an automatic trajectory planning system (ATPS) for painting robots by proposing a new trajectory planning scheme. The new scheme considers geometric modeling, painting mechanics, and robot dynamics to output an optimal trajectory (in the sense of coating thickness and painting time) based on the CAD data describing the shape of objects, The new scheme is implemented in SUN/4 workstation to develop an ATPS for painting robots. To test the validity of the new scheme and to illustrate the developed system, numerous runs are performed and analyzed.

• Proceedings of the Korean Society for Language and Information Conference
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• 2002.02a
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• pp.348-357
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• 2002

This paper discusses constraints on grammaticalization, a primarily diachronic process through which lexical elements take on grammatical functions. In particular, it will argue that two constraints on this process, namely Persistence and Lwering, explain the different distributional patterns of time-relationship adverbs in Japanese, Korean, English and German. Furthermore, it will suggest that the distributional difference between Japanese and Korean time-relationship adverbs is not an isolated phenomenon but is a reflection of the overall semantic typological differences between the two languages in the sense of Hawkins (1986).

• The Transactions of the Korea Information Processing Society
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• v.6 no.6
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• pp.1511-1519
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• 1999

We present efficient algorithms for transforming between binary images and quadtrees on the LABOR. For a binary image of size n ${\times}$ n, both algorithms run in $\theta$(1) time using n2 processors. These algorithms are optimal in the sense that the product of time and number of processors is asymptotically the same as the optimal sequential time which is $\theta$(n2).

• Educational Technology International
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• v.14 no.2
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• pp.215-228
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• 2013

In engineering education practical experiments is very important for each student, but due to the limitation of time and available resources such as laboratory equipment, space and instructors enough hands-on real experiments could not be provided to all students enrolled in the program throughout the academic year. In this sense web-based remote experiments through internet become a solution for engineering education and an emerging new paradigm for students and teachers. This paper presents the development of the web-based remote vibration experiment system for mechatronics education. Students can access this experimental equipment through an internet and conduct vibration experiment remotely without any restriction on time and place. IP address for data communication and web-service are assigned in local computer and then students receive experimental results and the captured pictures using network. The developed system provides real-time feedback of the tested results. Ubiquitous access to the system gained popularity from students.