비행친구: 청소년 비행의 원인인가, 아니면 결과인가?

정기원 한국청소년학회 2007 청소년학연구 Vol.14 No.1

Previous studies on juvenile delinquency have found that the adolescents with more delinquent friends engaged in more delinquent behaviors than those with less delinquent friends. But there appears to be little consensus on the direction of causal relationship between delinquent friends and delinquency. This study attempted to empirically examine the recursive causal relationship between delinquent friends and juvenile delinquency. Delinquent friend was hypothesized as predictor of delinquency by socialization model, and hypothesized as consequence of delinquency by selection model. The recursive causal relationship between delinquent friends and juvenile delinquency was hypothesized by enhancement model. A cross-lag panel design was used to analyze three annual waves of data for 3,017 adolescents from Korea Youth Panel Survey. The major finding of the study indicated that there were statistically significant relationships between delinquent friend at Time 1 and delinquency at Time 2 and Time 3, and between delinquent friend at Time 2 and delinquency at Time 3. The relationships between delinquency at Time 1 and delinquent friend at Time 2 and Time 3, and between delinquency at Time 2 and delinquent friend at Time 3 were also statistically significant. The findings suggested that association with delinquent friends was both predictor and consequence of engagement in delinquency, and that there was recursive causal relationship between delinquent friend and delinquency. The theoretical and practical implications of the study were discussed with reference to the direction of causal relationship between delinquent friend and delinquency. 청소년은 많은 시간을 친구와 함께 보내며, 친구에게 많은 의미를 부여하고, 그리고 친구로부터 많은 영향을 받기 때문에 친구관계는 청소년 비행 연구에 있어서의 핵심 주제 중의 하나가 된다. 특히 비행친구와 청소년 비행의 관계에서 그 인과관계의 방향에 대한 논란은 계속되어 왔다. 그러나 국내의 연구에서는 비행친구와 청소년 비행의 인과관계에 관한 실증분석은 전혀 이루어지지 않았다. 이 연구에서는 종단자료를 이용해 비행친구와 청소년 비행 간의 인과관계를 실증적으로 분석하는 데 연구의 목적을 두었다. 비행을 비행친구와의 교류에서 나타나는 사회학습과정의 결과로 보는 사회화 모형과 비행친구와의 교류는 비행을 저지른 청소년이 비슷한 유형의 친구를 선택한 결과라고 주장하는 선택 모형, 그리고 영향가설과 선택가설의 상호작용에 초점을 두는 강화 모형을 이론적 틀로 삼았다. 교차-시차 패널연구의 분석 모형을 이용하여 한국청소년패널조사의 중2 패널 1차년도(2003년)부터 3차년도(2005년)까지의 조사에 모두 응답한 3,017명의 자료를 분석하였다. 분석의 결과에서는 비행친구와 비행 간의 패널계수가 모두 통계적으로 유의하게 나타나 비행친구와 청소년 비행 사이에는 순환적 인과관계가 존재함을 보여 주고 있다. 이는 비행친구와의 교류는 청소년 비행의 원인이 되면서도 비행의 결과가 되고 있음을 의미하며, 영향가설과 선택가설의 상호작용에 초점을 두는 강화가설을 지지하고 있다. 이 연구는 비행친구와 청소년 비행 간에 나타나는 인과관계의 방향에 대한 두 대립가설을 실증적으로 검증하는 이론적 의의와 청소년 비행의 예방을 위한 대책 수립에 필요한 기초자료로 활용될 수 있다는 실천적 의의를 지닌다.

비행시차와 일중리듬

김인,Kim, Leen 대한수면의학회 1997 수면·정신생리 Vol.4 No.1

As jet lag of modern travel continues to spread, there has been an exponential growth in popular explanations of jet lag and recommendations for curing it. Some of this attention are misdirected, and many of those suggested solutions are misinformed. The author reviewed the basic science of jet lag and its practical outcome. The jet lag symptoms stemed from several factors, including high-altitude flying, lag effect, and sleep loss before departure and on the aircraft, especially during night flight. Jet lag has three major components; including external de synchronization, internal desynchronization, and sleep loss. Although external de synchronization is the major culprit, it is not at all uncommon for travelers to experience difficulty falling asleep or remaining asleep because of gastrointestinal distress, uncooperative bladders, or nagging headaches. Such unwanted intrusions most likely to reflect the general influence of internal desynchronization. From the free-running subjects, the data has revealed that sleep tendency, sleepiness, the spontaneous duration of sleep, and REM sleep propensity, each varied markedly with the endogenous circadian phase of the temperature cycle, despite the facts that the average period of the sleep-wake cycle is different from that of the temperature cycle under these conditions. However, whereas the first ocurrence of slow wave sleep is usually associated with a fall in temperature, the amount of SWS is determined primarily by the length of prior wakefulness and not by circadian phase. Another factor to be considered for flight in either direction is the amount of prior sleep loss or time awake. An increase in sleep loss or time awake would be expected to reduce initial sleep latency and enhance the amount of SWS. By combining what we now know about the circadian characteristics of sleep and homeostatic process, many of the diverse findings about sleep after transmeridian flight can be explained. The severity of jet lag is directly related to two major variables that determine the reaction of the circadian system to any transmeridian flight, eg., the direction of flight, and the number of time zones crossed. Remaining factor is individual differences in resynchmization. After a long flight, the circadian timing system and homeostatic process can combine with each other to produce a considerable reduction in well-being. The author suggested that by being exposed to local zeit-gebers and by being awake sufficient to get sleep until the night, sleep improves rapidly with resynchronization following time zone change. 누구나 시차가 큰 여행을 할 때 몇일 간 비행시차증이라고 불리우는 증상을 경험하게 된다. 비행시차증은 수면박탈, 비행요인, 지연요인의 복합적인 원인으로 인해 생기는 하나의 증상군이라고 말할 수 있다. 특히 빠른 시차변화로 인한 생리적 지연효과(Jet lag)는 외적 비동조화, 내적 비동조화, 그리고 수면상실의 결과를 낳는다. 인간의 수면을 조절하는 기전에 있어 일중체계가 중요하다. 즉, 평균적인 수면-각성주기는 중심체온의 주기와 내적 비동조화가 일어나더라도 수면경향, 졸리움, 자발적 수면 기간, 그리고 렘수면 경향은 중심체온의 내인성 일중주기에 따라 통제된다. 수면의 구성요소중에서 서파수면은 중심체온의 주기보다는 수면시작시간에 따라 나타나며 이전에 깨어있었던 기간이 길수록 강력하게 나타난다. 따라서 수면은 일중체계와 항상성 기전의 상호작용으로 조절된다. 비행시차 후에 변화되는 수면양상을 이해하는데 있어 일중 체계 이외에 도항상성 기전을 고려하여야한다. 수면에 대한 일중리듬체계의 영향과 수면의 항상성 과정이 비행시차후 도착지에서의 수면양상을 설 명할 수 있을 것이다. 도착지에서의 적응은 통과한 시간대 수, 여행 방향, 일주기 리듬의 부조화에 적응 할 수 있는 개인별 능력에 따라 다르다. 도착지의 시간적 단서에 빨리 노출되어 일중체계의 위상반응곡선에 의한 재동조화를 촉진시키고 수면의 항상성 과정을 고려하여 도착지의 밤 이전까지 충분히 깨어 있는 것이 Jet Lag를 극복하고 적응하는 지름길일 것이다.

비행시차(jet lag)에 의한 여행객의 수면-각성 주기의 변화

이승환,김인,서광윤,Lee, Seung-Hwan,Kim, Leen,Sub, Kwang-Yoon 대한수면의학회 1995 수면·정신생리 Vol.2 No.2

Jet lag can be defined as the cumulative physiological and psychological effects of rapid air travel across multiple time zone. The consequences of jet lag include fatigue, general malaise, sleep disturbances, and reductions of cognitive and psychomotor performance, all of which have been documented in experimental biological and air crew personnel studies. Thus authors tried to study the jet lag of natural travellers by modified self reporting sleep log. Total 61 healthy travellers was studied for 3 days before and 7 days after jet-flights across seven to ten time zone. The eastbound travelling group was 38 persons, aged 19 -70 and westbound travelling group was 23 persons, aged 13 - 69. Sleep onset time, wake-up time, sleep latency, awakening frequency on night sleep, awakening duration on night sleep, sleepiness at wake-up and nap length were evaluated. Our results suggested that the 7 to 10 time zone shift gave significant influence to traveller's sleep-wake cycles. The date which subjective physical condition was recovered on was $5.16{\pm}1.50$ day after arrivals for eastbound, while for westbound, $4.91{\pm}1.62$ day. In eastbound travelling, sleep onset time became later than baselines and could not recover until 7th day. But in westbound, it became earlier than baseline and could recover until 6th day. The mean score of 24-hour sleepiness was greater in eastboumd than westbound. Therefore the eastbound travelling caused more sleep-wake cycle disturbance and daytime dysfunction than westbound travelling. In other parameters, there was no definite difference between east and westbound. From our results, it was suggested that the symptom severity of jet lag was dependent on the travelling direction. To demonstrate more definite evidence, large sized data collections and comparision by age difference were needed.

연령에 따른 비행시차 후의 수면-각성주기 변화

김인,이승환,서광윤,Kim, Leen,Lee, Seung-Hwan,Suh, Kwang-Yoon 대한수면의학회 1996 수면·정신생리 Vol.3 No.2

Jet-lag can be defined as the cumulative physiological and psychological effects of rapid air travel across multiple time zones. Many reports have suggested that age-related changes in sleep reflect fundamental changes in the circadian system and in significant declines in slow wave sleep. Jet lag is a dramatic situation in which the changes of the phase of circadian process and homeostatic process of sleep occur. Thus the authors evaluatead the changes of sleep-wake cycle from jet lag by age. Thirty-eight healthy travellers were studied for 3 days before and 7 days after jet-flights across seven to ten time zone. They were aged 19-70, They trareled eastbound, Seoul to North America (USA, Canada). Sleep onset time, wake-up time, sleep latency, awakening frequency on night sleep, awakening duration on night sleep, sleepiness at wake-up and nap length were evaluated. Our results suggest that by the 7 to 10 time zone shift, the old age group was significantly influenced in sleep-wake cycles. The date on which subjective physical condition was recovered was $6.23{\pm}83$ day after arrivals for old age group, while for young and middle age group, $4.46{\pm}1.50$ day and $4.83{\pm}1.52$ day, respectively. In old age group, sleep onset time was later than baselines and could not recover untill 7th day. But in other groups, the recovery was within 5th day. Nap dura fion was longer in old age group through jet lag than younger age group. In other parameters, there was no definite difference among three age groups. Our results suggested that the old age was significantly influenced by the disharmony between internal body clock and sleep-wake cycle needed at the travel site. Thus we proved that recovery ability from jet lag was age-dependent as well as travelling direction-dependent. To demonstrate more definite evidence, EEG monitoring and staging of sleep were funthun encouraged.

국외근로자 비과세제도 개선방안 연구 : 국제선항공승무원을 중심으로

이기일,김수련,Lee, Ki Il,Kim, Soo Ryun 한국항공운항학회 2015 한국항공운항학회지 Vol.23 No.3

Since the tax-free system for overseas laborers was implemented in 1974, the tax-free limits of international air crew, overseas construction workers and crewmen of deep-sea fishing ships and ocean-going ships had been identical by 2005, but there are big differences, currently. The Ministry of Strategy and Finance pointed out the poor working environments and international competitiveness of the industries to explain the reason for the differential tax-free limit. From this perspective, the fairness of the tax-free system for overseas laborers was analyzed. This is an empirical study, based on the objective fact. The study finding showed that international air crew were working in the structural flight work environments to threaten the right of health due to jet lag and excessive exposure to high-altitude cosmic radiation. Therefore, it was analyzed there should be a proper system reform to apply the tax-free limits to international air crew which are identical to those applied to overseas construction workers and crewmen of deep-sea fishing ships and ocean-going ships, for a fair taxation.

카메라 검정요소에 따른 무임비행장치 입체도화 성능 분석

임평채(Pyung-Chae Lim),서정훈(Jung Hoon Seo),손종환(Jonghwan Son),김태정(Taejung Kim) 대한공간정보학회 2018 한국공간정보학회 학술대회 Vol.2018 No.11