• Phonetics and Speech Sciences
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• v.13 no.1
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• pp.73-79
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• 2021

This study investigated the change in lip movement during speech according to aging. For the study, 15 elderly women with an average of 69 years and 15 young women with an average of 22 years were selected. To measure the movement of the lips, the ratio between the minimum point and the maximum point of movement when pronouncing a double vowel was analyzed in pixel units using image analysis software. For clinical utility, the software was produced by applying an automated algorithm and compared with the results of handwork. This study found that the range of the width and length of lips in double vowel tasks was smaller for the elderly than that of the young. A strong positive correlation was found between manual and automated methods, indicating that both methods are useful for extracting lip contours. Based on the above results, it was found that the range of the lips decreased when ignited as aging progressed. Therefore, monitoring the condition of lip performance by simply measuring the movement of lips before aging progresses, and performing exercises to maintain lip range, will prevent pronunciation problems caused by aging.

• The KIPS Transactions:PartA
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• v.8A no.2
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• pp.81-90
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• 2001

As the rapid growth of Internet, computer systems are growing in its size and complexity. To meet high availability requirements for the systems, one usually uses both hardware and software fault tolerance techniques. To prevent failures of computer systems from software-aging phenomenon that come from long mission time, we adopt software rejuvenation method that stops and restarts the software in the servers intentionally. The method makes the systems clean and healthy state in which the probability of fault occurrence is very low. In this paper, we study how switchover time affects software rejuvenation of primary-backup server systems. Through experiments, we find that switchover time is an essential factor for deciding the rejuvenation policy.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.4
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• pp.61-69
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• 2019

Accelerated aging test for the double base propellant was carried out at three different temperatures (60, 70, and $75^{\circ}C$) for over a year. To evaluate the aging characteristics of the double base propellant, the stabilizer contents and thermal decomposition kinetics were analyzed by using high performance liquid chromatography (HPLC) and AKTS-Thermokinetics software. As a result, stabilizer contents in the double base propellant gradually decreased according to the aging temperature and aging duration. The consumption rate of 2-NDPA in the accelerated aged propellants showed that it was two times faster at $75^{\circ}C$ in compared with ther rate at $70^{\circ}C$. These experimental values were simulated by the SB kinetic model, and it was shown that the two-step model with constant reaction orders n1=1 and n2=0 best describes the process of the stabilizer depletion for the double base propellant.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.2
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• pp.201-206
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• 2019

Rejuvenating a system periodically during the most idle time of the system reduces unexpected downtime caused by software aging and increases its availability. In general, software rejuvenation can be largely divided into two broad categories: time-based rejuvenation policy and condition-based rejuvenation policy. In time-based rejuvenation policy the software rejuvenation is triggered at scheduled time epochs with fixed time intervals, while in condition-based rejuvenation policy the software rejuvenation is performed when system state is checked to satisfy a specific condition. Conditionbased policy adds extra cost to the system due to system monitoring and aging estimation. This paper presents a stochastic model for analyzing time-based software rejuvenation mechanism, where the rejuvenation is triggered at scheduled time epochs with fixed time intervals, and provides an analytical solution for the steady-state availability, the user-perceived availability, and the corresponding cost.

• Therapeutic Science for Rehabilitation
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• v.11 no.2
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• pp.25-37
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• 2022

Objective : Through the bibliographic analysis method, the flow of research is grasped from a macroscopic point of view and the connection system of key words is conducted. The purpose of this is to provide basic data for conducting research on aging anxiety and lifestyle. Methods : Among the bibliographic analysis methods, a citation analysis method that identifies the association based on the number of citations and a simultaneous appearance word analysis method that identifies the association based on the number of keywords appeared was used. VOSviewer was used to cluster and chart the analyzed information. Results : The frequency of occurrence of papers by year showed a gradual increase until 2017 and a rapid increase from 2018. In the field of research paper study, research was most actively conducted in the field of psychiatry. In the citation analysis, the United States, Australia, and the United Kingdom showed high correlation with each other, and as a result of conducting simultaneous word analysis on major keywords, words with high association with aging anxiety were found to be depression. Conclusion : This study is meaningful in that it grasped the flow of aging anxiety and lifestyle research from a macroscopic point of view using a bibliographic analysis method. Based on this, it is expected to understand the importance of lifestyle from the preventive point of view of aging and to be used as basic data for intervention and related education.

• Journal of the Korea Computer Industry Society
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• v.3 no.2
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• pp.227-234
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• 2002

An cluster web server system, one has the problem that does the low availability occured by the high chance of the server failures and it is not easy to provide high performance and availability occuring software aging. In this paper, running cluster web sewers consists of n primary servers and k backup servers, propose software rejuvenation model on performance and switchover time. Based on the various system operational parameters, we calculate to evaluate the rejuvenation policy such steady-state probabilities, availability, and downtime cost. And we validate the solutions of mathematical model by experiments based on various operation parameters and fud that the software rejuvenation method can be adopted as prventive fault tolerant technique for stability of system.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.8
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• pp.730-740
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• 2000

The software rejuvenation method for highly available multiplex systems uses a pro-active fault-tolerant approach to handle system failures. The software rejuvenation prevents failures from occurring, while the previous methods recover from failures after happening. Especially, since the software aging proceeds fast in the software used for the multimedia mobile computing due to the loss of communications or data, the preventive method from failures using software rejuvenation can be used for the multimedia mobile computing. In this paper, according to the operational parameters such as rejuvenation period, rejuvenation time, failure rate and repair rate of the servers, number of running servers, duration of running time, and type of running modes, we calculate steady-state probabilities, downtime, availability, and cost of the multiplex systems using software rejuvenation method. We validate the closed-form solutions of the mathematical model by experiments based on various operational parameters and find that the software rejuvenation method can be adopted as preventive fault-tolerant technique. The failure rate and unstable rate of the servers are essential factors for the decision making of the rejuvenation policies.

• Journal of KIISE:Software and Applications
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• v.28 no.6
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• pp.403-413
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• 2001

시스템이 진화와 노화를 거듭하는 경우 프로그램을 이해하는데 있어서 가장 정확한 문서는 기존의 시스템 자체에서 추출되어진 정보이다. 프로그램의 이해를 돕기 위한 분석기법중의 하나인 프로그램 슬라이싱은 1984년 Weiser에 의해서 소개되어진 이후 다양한 방향으로 연구가 진행되어져 왔다. 특히, 생성되어지는 프로그램 슬라이스가 사이즈가 크고 충분히 집약적이지 못하다는 문제점과 슬라이스의 계산방법이 효율적이지 못하다는 문제점을 극복하기 위하여 여러 가지 방법들을 시도되어 왔다. 본 논문은 고전적인 슬라이싱 기준에 새로운 파라미터를 추가함으로써 제외개념을 이용하여 보다 함수적으로 응집력있고, 사이즈가 작은 슬라이스를 생성하는 선택 슬라이스를 제시하며 이 선택슬라이스를 계산하기 위한 효율적인 방법을 기술한다. 데이터와 제어의 흐름을 이용하여 선택 슬라이싱을 정의하고, 선택 슬라이싱을 위한 종속그래프를 정의하고 이를 사용하여 선형적 시간 내에 선택 슬라이스를 생성하는 알고리즘을 기술한다.

• Journal of the Korea Computer Industry Society
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• v.3 no.1
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• pp.77-84
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• 2002

An cluster system used consist of large number of running servers, one has the problem that does the low availability occured by the high chance of the server failures and it is difficult to provide occuring software aging. In this paper, running cluster web servers consists of n primary servers and k backup servers, based on the operational parameters such as number of running primary servers, number of backup severs, rejuvenation period, rejuvenation time, failure rate of sewers, repair rate of servers, unstable rate of servers. We calculate to evaluate the rejuvenation policy such steady-state probabilities, downtime, availability, and downtime cost. We validate the solutions of mathematical model by experiments based on various operation parameters and find that the software rejuvenation method can be adopted as prventive fault tolerant technique for stability of system. The failure rate and unstable rate of the servers are essential factors for decision making of the rejuvenation policies.

• Therapeutic Science for Rehabilitation
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• v.12 no.1
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• pp.65-78
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• 2023

Objective : The typical decline in function due to aging includes limitations in vision, hearing, cognitive function, and activities of daily living. Therefore, this study evaluated the mediating effect of cognitive function on the relationship between vision and hearing and activities of daily living. Methods : The participants in this study were 36,767 persons from the long-term care database on older adults provided by the National Health Insurance Sharing Service. The extracted variables were: (i) independent variables: visual and hearing; (ii) dependent variables: basic and instrumental daily living activities; and (iii) mediator variables: cognitive function. Regression analysis was performed evaluate the mediating effects of the extracted variables. Results : Cognitive function showed a mediating effect of 30% on the relationship between vision and basic daily life activities and 42% in the relationship with instrumental daily life activities. The mediating effect was 50% in the relationship between hearing and basic activities of daily living, and 53% in the relationship with instrumental activities of daily living. Conclusion : Prevention programs for functional decline due to aging are in progress in Korea. Based on the results of this study, establishing a prevention program would help promote successful aging.