• Journal of Biomedical Engineering Research
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• v.20 no.3
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• pp.315-321
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• 1999

The purpose of this study is to develop a mathematical model for system identification in order to predIct muscle force based on eledromyographic signal. Therefore, a finding of the relalionship between characteristics of electromyographic signal and the corre spondng muscle force should be necessiiry through dynamic, joint model. To develop the dynamic joint model, the upper limb mcludmg the wrist and elbow joint has been considered. The kinematic and dynamic data, such as joint angular displacement, velocity, deceleration along with the moment of inertla, required to establish the dynamic model has been obtained by electrical flexible goniometer which has two degree-of-frcedoms. ln this model, muscle force can be predicted only electromyographs through the relationship between the integrated lorce and the mtegrated electromyographic signal over the duration of muscle contraclion in this study.

• The Korean Journal of Applied Statistics
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• v.37 no.2
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• pp.255-263
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• 2024

GDP represents the total market value of goods and services produced by all economic entities, including households, businesses, and governments in a country, during a specific time period. It is a representative economic indicator that helps identify the size of a country's economy and influences government policies, so various studies are being conducted on it. This paper presents a GDP growth rate forecasting model based on a dynamic factor model using key macroeconomic indicators of G20 countries. The extracted factors are combined with various regression analysis methodologies to compare results. Additionally, traditional time series forecasting methods such as the ARIMA model and forecasting using common components are also evaluated. Considering the significant volatility of indicators following the COVID-19 pandemic, the forecast period is divided into pre-COVID and post-COVID periods. The findings reveal that the dynamic factor model, incorporating ridge regression and lasso regression, demonstrates the best performance both before and after COVID.

• Journal of Korean Neurosurgical Society
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• v.63 no.3
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• pp.272-278
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• 2020

Compared to any other decade, the last two decades have been the most dynamic period in terms of advances in the knowledge on spinal dysraphism. Among the several factors of rapid advancement, such as embryology during secondary neurulation and intraoperative neurophysiological monitoring, there is no doubt that Professor Dachling Pang stood high amidst the period. I review here the last two decades from my personal point of view on what has been achieved in the field of spinal dysraphism, focusing on occult tethered cord syndrome, lumbosacral lipomatous malformation, terminal myelocystocele, retained medullary cord, limited dorsal myeloschisis and junctional neural tube defect. There are still many issues to revise, add and extend. Profound knowledge of basic science is critical, as well as refined clinical analysis. I expect that young scholars who follow the footsteps of precedent giants will shed bright light on this topic in the future.

• Journal of Korean Institute of Industrial Engineers
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• v.24 no.1
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• pp.51-59
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• 1998

This paper presents a new present value measure, the dynamic present value, or DPV. DPV takes into account not only the value of the realized cash flow but also that of potential cash flow. The DPV approach enables the analyst to observe differences in the present value of the alternatives every period over the whole time period of interest. This is the most fundamental advantage of the DPV approach over the traditional present value approach in which the present value of the alternatives is evaluated only one particular point of time. The concepts of the realized and potential cash flows are also developed in this paper. These new concepts are found to be useful elements in evaluating economic alternatives.

• Journal of the Korean Operations Research and Management Science Society
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• v.6 no.1
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• pp.57-64
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• 1981

The continuous increase of crude oil consumption has struck great impact into the world economy, When we consider disadvantageous articles in contract for oil import, it would be desirable to import in batch the total quantity of crude oil contracted, but which is not available under the present situation which has many constraints This paper treats of the ways to deliver the crude oil in a given period so as to maximize the profit derived from the sales of oil products, To do this we should consider the prices of crude oil and oil products, inventory cost, transportation cost, oil refinement cost, and fluctuations of these parameters in a given period. The case of Korea Oil Corporation is treated in this paper to generalize the problem of crude oil transportation from Middle East and formulated in a mathematical programming. This programming is transformed into Dynamic Programming through specifing states, stages, payoffs, and recursive function. To clarify these procedure and methods, the case of Korea Oil Corporation is dealt with again and demonstrated in detail.

• International Journal of Aeronautical and Space Sciences
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• v.8 no.1
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• pp.21-31
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• 2007

Relaxed Static Stability (RSS) concept has been applied to improve aerodynamic performance of modern version supersonic jet fighter aircraft. The T-50 advanced supersonic trainer employs the RSS concept in order to improve the aerodynamic performance. And the flight control system stabilizes the unstable aircraft and provides adequate handling qualities. The T-50 longitudinal control laws employ a proportional-plus-integral type controller based on a dynamic inversion method. The longitudinal dynamic modes consist of short period with high frequency and phugoid mode with low frequency. The design goal of longitudinal control law is optimization of short period damping ratio and frequency using Lower Order Equivalent System (LOES) complying the requirement of MIL-F-8785C. This paper addresses phugoid mode characteristics such as damping ratio and natural frequency that is affected by the nonlinear control laws such as angle of attack limiter, auto pitch attitude command system and autopilot of pitch attitude hold.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.61-64
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• 2000

This paper analyzes a dynamic lot-sizing problem, in which the order size of multiple products and a single container type are simultaneously considered. In the problem, each order (product) placed in a period is immediately shipped immediately by containers in the period and the total freight cost is proportional to the number of each container type employed. Also, it is assumed that backlogging is not allowed. The objective of this study is to determine the lot-sizes and the shipping policy that minimizes the total costs, which consist of ordering costs, inventory holding costs, and freight costs. Because this problem is NP-hard, we propose a heuristic algorithm with an adjustment mechanism, based on the optimal solution properties. The computational results from a set of simulation experiment are also presented.

• Structural Engineering and Mechanics
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• v.9 no.3
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• pp.257-268
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• 2000

The seismic design recommendations of the Jordan Code for Loads and Forces (JC) are evaluated, based on comparisons with analytical studies and the Uniform Building Code. It was established that the overall safety ensured by the implementation of these recommendations is not consistent with the established seismic risk in Jordan and the intended objectives of the code. A new zoning map is proposed with effective peak ground acceleration values. The different period formulae of the code were studied and were found to grossly underestimate the fundamental period when compared with analytically derived values or other codes' formulae. Other factors including the dynamic, soil, importance and behavior factors are discussed. It was determined that the JC's lateral load distribution formulae clearly lead to smaller internal forces than both dynamic analysis and UBC loads, even when those loads are normalized to give the same base shear. The main reason for this is attributed to the limited allowance for a backlash force in the JC.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.125-127
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• 2007

현재 차량 내 네트워크에서 주로 쓰이는 CAN 프로토콜은 네트워크 내에 다수의 노드가 연결되어 동작하는 경우 우선순위가 낮은 메시지의 전송지연이 심각하게 발생할 수 있다. 이를 해결하기 위해 다양한 제어 방법들이 제안되어 시험되고 있는데, 본 논문에서는 동적 ID 차당 기법을 연로전지 하이브리드 자동차 네트워크 시스템에 적용하여 각 장치들간의 메시지 전송 지연문제를 해결 하며, 또한 이로 인해 발생하는 차량 내 네트워크 시스템의 수행 주기 변화의 문제점을 샘플링 주기 결정 기법을 이용하여 효율적으로 해결하였다.

• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.63-66
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• 2001

In the Poolco model, the bidding game is executed periodically. The player participating to the bidding game accumulates the information of others' strategies and payoffs through the repeated process. Thereby, he is able to map out how he gets his maximum profit, and proceed to the optimal strategy region. This paper shows the algorithm for a player to determine his strategy in t period based the information of the game results of t-1, t-2 period. And this algorithm can be formulated by using Dynamic game theory.