• Title/Summary/Keyword: Frequency instability

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Estimating the Impact on Aviation Demand by High Speed Railroad Service in Korea (고속철도 개통으로 인한 항공수요 변화에 대한 추정)

  • Park, Yong-Hwa;Kim, Yeon-Myung;Oh, Sung-Yeol
    • Journal of Korean Society of Transportation
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    • v.22 no.6
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    • pp.47-54
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    • 2004
  • Recently, a large reduction in domestic aviation demand had roughly shown in the range between 34% and 75% in east central and western corridor of Korea. The reasons for the drop in air traffic demand were the provisioning of several new highway serveces and the national economic difficulties. Since April 2004, moreover, the Korea Train Express(KTX) was operated between Seoul and Daegu in the first phrase of 293Km in KTX operational distance and 258Km in air route distance. The operation of KTX significantly impacted air traffic volume, particularly on the overlapped air routes with KTX routes. This study analyzed the effects on air traffic demand in accordance with the opening of KTX by applying the Stated Preference (SP) survey method, the survey conducted prior to 8 months of the KTX initiative. Also, the comparison of the decreased demand forecast by SP analysis and actual revealed traffic volume during two months service after inauguration of KTX was conducted. The Seoul-Daegu route was analysed using the 3 variables considered access and egress time, fare rate, operational frequency. The result obtained from the analysis showed that air users would be preferred only 14%. Comparatively, however, the actual revealed air passengers after the opening KTX were remained 28%, The less "decreased demand" was caused by the instability of the KTX's operation in the initial stage. Therefore, small numbers of passenger were preferable to airservices rather than high speed railroad service.

An exploratory study on factors related to types of never-married among adult men and women (성인 비혼 남녀의 비혼 유형 관련 요인 탐색 연구)

  • Kim, Ji-Yu;Cho, Hee-Sun
    • Journal of Family Relations
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    • v.23 no.3
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    • pp.201-228
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    • 2018
  • Objectives: The objectives of this study were to classify never-married types of adult men and women and explore factors related to these types. Never-married types were categorized into 4 types according to continuity and voluntariness: continuous voluntary type; changed voluntary type; continuous non-voluntary type; and changed non-voluntary type. Factors related to types of being single were examined in terms of socio-demographic factors, individual and psychological factors (self-esteem, depression), dating relationship factors (current relationship status), original family factors (parental conflict, relationship with parents, parents' demand for marriage), marriage related factors (division of roles after marriage), and occupation related factors (work values, employment instability). Method: As for research method, a survey was conducted with never-married adult men and women between the ages of 35 and 49 living in Seoul, Gyeonggi or Incheon areas. Of 300 copies of questionnaire distributed, data from 295 copies were processed using SPSS 24.0 program for multinomial logit analysis. Results: The study results showed that, of never-married men respondents, continuous voluntary type accounted for 20.5%; changed voluntary type 18.9%; continuous non-voluntary type 49.6%; and changed non-voluntary type 11.0%. It was found that the factors related to continuous non-voluntary type among never-married men are age, religion, average monthly income, while the factors related to changed voluntary type are religion, self-esteem, depression, and frequency and strength of parental conflict, while the factor related to changed non-voluntary type men was living with parents. Examining never-married women respondents, it was found that, continuous voluntary type accounted for 33.9%; changed non-voluntary type 19.6%; continuous non-voluntary type 22.6%; and changed voluntary type 23.8%. The factor related to continuous non-voluntary type among never-married women was parents' demand for marriage, while the factors related changed voluntary type were age, depression and strength of parental conflict. Also, the factors related to changed non-voluntary type of never-married women were age, religion, living with parents, depression and parents' demand for marriage. Conclusion: In conclusion, it was found that continuous non-voluntary type formed the largest group among never-married men, whereas continuous voluntary type was the majority in never-married women. Both never-married men and women chose to remain single when they are living with their parents and their parental conflict is intense. Parents' demand for marriage was related to women, but not to men.

East Asian Security in the Multipolar World Order: A Review on the Security Threat Assessment of the Korean Peninsula Amid the Restructuring of International Order (다극체제와 동아시아 안보: 국제질서 재편에 따른 한반도 안보 위협 논의의 재고찰)

  • Lee, Sungwon
    • Analyses & Alternatives
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    • v.6 no.2
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    • pp.37-78
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    • 2022
  • The U.S.-led international order, sustained by overwhelming national power since the end of the Cold War, is gradually being restructured from a unipolar international system to a bipolar international system or a multipolar international system, coupled with the weakening of U.S. global leadership and the rise of regional powers. Geopolitically, discussions have been constantly raised about the security instability that the reshaping of the international order will bring about, given that East Asia is a region where the national interests of the United States and regional powers sharply overlap and conflict. This study aims to critically analyze whether security discussions in Korea are based on appropriate crisis assessment and evaluation. This paper points out that the security crisis theory emerging in Korea tends to arise due to threat exaggeration and emphasizes the need for objective evaluation and conceptualization of the nature and the level of threats that the restructured international order can pose to regional security. Based on the analysis of changes in conflict patterns (frequency and intensity), occurring in East Asia during the periods divided into a bipolar system (1950-1990), a unipolar system (1991-2008), and a multipolar system (2009-current), this study shows that East Asia has not been as vulnerable to power politics as other regions. This investigation emphasizes that the complexity of Korea's diplomatic and security burden, which are aggravated by the reorganization of the international order, do not necessarily have to be interpreted as a grave security threat. This is because escalating unnecessary security issues could reduce the diplomatic strategic space of the Republic of Korea.

Heart Rate Variability and Autonomic Activity in Patients Affected with Rett Syndrome (Rett 증후군 환자에서의 자율신경 활성도 및 심박수 변이도 측정)

  • Choi, Deok Young;Chang, Jin Ha;Chung, Hee Jung
    • Clinical and Experimental Pediatrics
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    • v.46 no.10
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    • pp.996-1002
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    • 2003
  • Purpose : In Rett syndrome patients, the incidence of sudden death is greater than that of the general population, and cardiac electrical instability including fatal cardiac arrhythmia is a main suspected cause. In this study, we are going to find out the possible cause of the higher risk of sudden death in Rett patients by the evaluation of heart rate variability, a marker of cardiac autonomic activity and corrected QT intervals. Methods : Diagnosis of Rett syndrome was made by molecular genetic study of Rett syndrome (MECP2 gene) or clinical diagnostic criteria of Rett syndrome. Heart rate variability and corrected QT intervals were measured by 24 h-Holter study in 12 Rett patients, and in 30 age-matched healthy children with chief complaints of chest pain or suspected heart murmurs. The were compared with the normal age-matched control. Results : Patients with total Rett syndrome, classic Rett syndrome, and Rett variants had significantly lower heart rate variability(especially rMSSD)(P<0.05) and longer corrected QT intervals than age-matched healthy children(P<0.05). Sympathovagal balance expressed by the ratio of high to low frequency(LF/HF ratio) also showed statistically significant differences between the three groups considered(P<0.05). Conclusion : A significant reduction of heart rate variability, a marker of autonomic disarray, suggests a possible explanation of cardiac dysfunction in sudden death associated with Rett syndrome.

Korea's Terrorist Environment and Crisis Management Plan (한국의 테러환경과 위기관리 방안)

  • Jang, Sung Jin;Kim, Young-Hyun;Shin, Seung-Cheol
    • Korean Security Journal
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    • no.52
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    • pp.73-91
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    • 2017
  • This study is based on the political and economic standpoint of each country, Use advanced equipment to prevent new terrorism from causing widespread damage, In order to establish a countermeasures against terrorism in accordance with the reality of Korea, which is effective in responding to terrorist attacks, Korea conducted a SWOT analysis of the terrorist environment and terrorist environment through specialists. First, internal strengths of Korea 's terrorist environment include stable security situation, weakness of religious and ethnic conflicts, strong regulation and control of firearms, and counter terrorism capabilities and know - how accumulated during major international events. Second, the internal weaknesses of the terrorist environment in Korea include the insecurity of the people, the instability caused by the military confrontation with North Korea, the absence of anti-terrorism law system, the difficulty of terrorism control and management by the development of the Internet and IT technology. Third, the external opportunities for Korea 's terrorist environment are as follows: ease of supplementation and learning through cases of foreign terrorism failure, ease of increase of terrorist budget and support with higher terrorism issues, strengthening of counterterrorism through military cooperation with allied nationsRespectively. Fourth, the external threats to the terrorist environment in Korea are the increase of social dissatisfaction due to the continuous influx of defectors and foreign workers, the goal of terrorism from international terrorist organizations through alliance with the United States,Increased frequency of incidents, and increased IS coverage of terrorism around the world. In addition, the SWOT in - depth interviews on the terrorist environment of the expert group were conducted to diagnose and analyze the problems, terrorism awareness and legal system in the Korean terror environment. The results of the study are summarized as follows.First, the basic law on terrorism should be enacted.Second, the establishment of an integrated anti-terrorism organization.Third, securing and nurturing specialized personnel in response to terrorism.

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