• Journal of the Korean Operations Research and Management Science Society
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• v.24 no.4
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• pp.13-26
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• 1999

When we try to design a production planning system for a manufacturing company, it is a time consuming task to analyze various planning activities and identify inter-relationship among a lot of decisions made for the production planning. Most of the research efforts have been concentrated to well-organized independent decision-making problems that may usually be identified only after analyzing the characteristics of the decision-making process as a whole. In this paper, a methodology is suggested to characterize the whole process of the production planning for a manufacturing company and reduce the complexity of decision-making problems. The methodology is based on an experience of developing a production planning software for an automobile component manufacturer in korea. First, it is explained how to identify and represent the dependency among various decision-making variables. And a methodology is proposed to analyze the identified dependency among decision variables and identify decision-making process. Lastly, a practical example is provided to illustrate the analysis procedure in this paper.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.1196-1198
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• 1992

In field oriented control of Induction motors, speed sensor is required, which reduces the sturdiness of drive system and together with the expenditure of hardware for faultless transmission and processing of sensor signals it causes considerable expenses. These expensive sensors can be replaced by speed sensorless concept. And for good control, the knowledge of the rotor flux component of the rotor resistance are needs. Thus, this paper is based on a Extended Kalman Filter( EKF ) that estimates the state variables that are required for the control by only measuring the line voltages and currents of the machine. The rotor time constant and speed estimated by the EKF shows satisfactory agreement with the real values, with the simulation approaches.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.5
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• pp.64-70
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• 1995

This paper presents a practical approach to evaluate the reliability indices of electric distribution systems. The use of reliability evaluation is placed with framework of distribution system planning and operation. In this paper, the reliability model is based on an analytical method, connecting component failure to load point outage in each section. Five cases are reported in the paper to study the effect of varying failure rates and repair times on real distribution systems. Simulations are preformed by the developed reliability evaluation program.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1718-1723
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• 2007

The Probe Card is a test component which is to classify the good semiconductor chips before the packaging. The yield of semiconductor product can be better from analysis of probe test information. Recently the technology of the probe card needs narrow width and large amount of probe tip. In this research, the probe tip based on the MEMS(micro electro mechanical system) technology was designed and fabricated to improve the reliability of the test and to meet 2-dimensional Array of tip. The mechanical and electrical properties of proposed tip were evaluated and it has over 100,000 of repetition times in the condition of 5gf, $20{\mu}m$ Over Drive.

• Korean Journal of Pharmacognosy
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• v.20 no.4
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• pp.205-214
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• 1989

The sensing of odour compounds in gas phase is an attractive target in recent sensor technology. Based on the finding that a plant leaf can respond to various gas molecules by changing its potential, biosensing system using a plant leaf has been investigated for the detection of odour compounds. A leaf of some plant species responded to odour compounds directly by changing its potential $5{\sim}10\;mV$. That the leaf was actually sensing an odour was much more remarkably detected from the difference between the response profile to pure $CO_2$ gas and that to $CO_2$ gas containing odour compounds. Then the quantitative study (ppb level) is now being performed on the response of a tobacco leaf to benzyl acetate; a component of jasminelike odours. The concept of biosensing and its significance are also described from the viewpoint of sensor technology.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.4
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• pp.432-438
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• 2008

This paper presents a new jetting dispenser driven by a piezoelectric actuator at high operating frequency to provide very small dispensing dot size of adhesive in modern semiconductor packaging processes. After describing the mechanism and operational principle of the dispenser, a mathematical model of the structured system is derived by considering behavior of each component such as piezostack and dispensing needle. In the fluid modeling, a lumped parameter method is applied to model the adhesive whose rheological property is expressed by Bingham model. The governing equations are then derived by integrating the structural model with the fluid model. Based on the proposed model, dispensing performances such as dispensing amount are investigated with respect to various input trajectories.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.11a
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• pp.143-146
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• 2009

브로드밴드 네트워크의 발전으로 네트워크를 통해 콘텐츠를 제공하는 TV포털이나 IPTV 서비스가 활성화되고 있으며 시청자들은 온디멘드 서비스에 익숙해지고 있다. 하지만 지상파 방송사는 방통 융합 서비스의 핵심이라고 할 수 있는 양방향 네트워크를 갖고 있지 않으므로 증가하고 있는 시청자의 온디멘드 서비스 요구에 적절히 대응하지 못하고 있는 실정이다. 따라서 지상파 방송사의 입장에서는 상대적으로 운용비용이 많이 드는 인터넷과 같은 양방향 네트워크의 전송 효율을 높이기 위해 온에어 DTV 채널을 기반으로 인터넷을 접목하여 TV와 PC 나아가서는 모바일 단말과 같은 다양한 단말에서 콘텐츠와 관련 데이터를 공유할 수 있는 DTV 기반의 크로스미디어 서비스가 적합하다. 이에 본 논문에서는 이러한 크로스미디어 서비스를 제공하기 위해 필요한 콘텐츠 제작 요소기술과 온에어와 인터넷을 통해 콘텐츠와 관련 정보를 송수신하는 요소기술을 제안하는 바이다.

• Ocean Systems Engineering
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• v.6 no.2
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• pp.191-201
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• 2016

Stern bearing is a key component of marine propulsion plant. Its environment is diverse, working condition changeable, and condition severe, so that stern bearing load is of strong time variability, which directly affects the safety and reliability of the system and the normal navigation of ships. In this paper, three affecting factors of the stern bearing load such as hull deformation, propeller hydrodynamic vertical force and bearing wear are calculated and characterized by random theory. The uncertainty mathematical model of stern bearing load is established to research the relationships between factors and uncertainty load of stern bearing. The validity of calculation mathematical model and results is verified by examples and experiment yet. Therefore, the research on the uncertainty load of stern bearing has important theoretical significance and engineering practical value.

• Wind and Structures
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• v.13 no.2
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• pp.207-220
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• 2010

The 'chain reaction' effect of the interaction between wind pressure and windborne debris is likely to be a major cause of damage to residential buildings during severe wind events. The current paper (Part II) concerns the quantification of such pressure-debris interaction in an advanced vulnerability model that integrates the debris risk model developed in Part I and a component-based wind-pressure damage model. This vulnerability model may be applied to predict the cumulative wind damage during the passage of particular hurricanes, to estimate annual hurricane losses, or to conduct system reliability analysis for residential developments, with the effect of windborne debris fully considered.

• Structural Engineering and Mechanics
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• v.66 no.4
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• pp.515-529
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• 2018

Multiple hazards (multihazard) conditions may cause significant risk to structures that are originally designed for individual hazard scenarios. Such a multihazard condition arises when an earthquake strikes to a bridge pre-exposed to scour at foundations due to flood events. This study estimates the impact spectrum of flood-induced scour on seismic vulnerability of bridges. Characteristic river-crossing highway bridges are formed based on the information obtained from bridge inventories. These bridges are analyzed under earthquake-only and the abovementioned multihazard conditions, and bridge fragility curves are developed at component and system levels. Research outcome shows that bridges having pile shafts as foundation elements are protected from any additional seismic vulnerability due to the presence of scour. However, occurrence of floods can increase seismic fragility of bridges at lower damage states due to the adverse impact of scour on bridge components at superstructure level. These findings facilitate bridge design under the stated multihazard condition.