• Title, Summary, Keyword: Seasonality

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On the Study of the Seasonality Precipitatio over South Korea (남한의 강수 계절성에 관한 연구)

  • Yoon, Hee-Jung;Kim, Hee-Jong;Yoon, Ill-Hee
    • Journal of the Korean earth science society
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    • v.27 no.2
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    • pp.149-158
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    • 2006
  • This study analyzes the seasonality precipitation using precipitation data from 1973 to 2001 over South Korea. The Seasonality Index and Annual variation of the Seasonality Precipitation were investigated from sixty-three observation stations. The Seasonality Precipitation means the degree of the precipitation falling intensively for some specific months. Spatially, precipitation that has a strong characteristic of regional shower is defined as seasonal precipitation. Precipitation forms are changed with various reasons and mainly the sporadic and local shower precipitation after rain spell in summer. Especially there appears a tendency that this kind of precipitation is sharply increasing in 1990's. Seasonality Index is used as a method to understand seasonal precipitation. If the yearly rainfall is concentrated for some specific months, Seasonality Index is growing gradually. It is confirmed that there is a tendency that all the from sixty-two observation stations Seasonality Index. While Seasonality Index over South of Korea concentrated from June to August because of the summer rain spell in the past ($1973{\sim}1982$), there appears to be a tendency that it concentrated from August and September since the mid 1990's. From the analysis of seasonal precipitation intensity distribution, most of southern Korea is under seasonality precipitation intensity 4. The seasonality precipitation intensity classification results are as follow: most of the observation stations were on a scale intensity of 3 and 4 in the past but currently reads seasonality precipitation intensities of 5 and 6.

Seasonal Changes in Mood and Behavior and Associated Factors of Seasonality in Korean Bipolar Disorder Patients and Normal Controls (양극성 장애 환자와 정상인에서 계절성의 양상과 관련 요인 탐색)

  • Choi, Jungmi;Baek, Ji Hyun;Kim, Ji Sun;Choi, Ji Sun;Noh, Jihae;Nam, Hee Jung;Lee, Dongsoo;Hong, Kyung Sue
    • Korean Journal of Biological Psychiatry
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    • v.17 no.3
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    • pp.153-160
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    • 2010
  • Objectives : Recurrence of mood episodes associated with a specific season has been described in various mood disorders. Seasonal change in mood and behavior as a lifetime trait is also observed in healthy individuals. This study aimed at comparing the lifetime trait of seasonal variations of mood and behavior between bipolar disorder patients and controls as well as investigating associated factors of seasonality. Methods : Subjects were ninety-four clinically stable patients with bipolar disorder and 188 age- and sex-matched healthy controls. Seasonality of mood and behavior was assessed retrospectively on lifetime basis using Seasonal Pattern Assessment Questionnaire(SPAQ). Results : The patient group showed a higher median global seasonality score(GSS) of SPAQ and a higher rate of seasonal affective disorder(SAD) compared to the control group(p < 0.0001). For subjects showing prominent seasonality, the seasonal symptom profile and seasonal pattern was similar in both patient and control groups. In addition to the diagnosis, female gender was shown to be a predictor of seasonality in the multiple linear regression analysis(p = 0.045). Conclusion : This study suggests that lifetime trait of seasonality may be related to the susceptibility of bipolar disorder.

The Economic Crisis in Greece and Its Impact on the Seasonality of Suicides in the Athens Greater Area

  • Christodoulou, Christos;Efstathiou, Vasiliki;Michopoulos, Ioannis;Gkerekou, Maria;Paraschakis, Antonios;Koutsaftis, Filippos;Douzenis, Athanassios
    • Psychiatry investigation
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    • v.14 no.1
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    • pp.16-20
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    • 2017
  • Objective The economic crisis and the implementation of austerity measures in Greece lead to significant socioeconomic changes. The effects of the crisis were mainly felt by the Greek population during the years 2011 and 2012. This study aimed to investigate the impact of Greece's economic crisis on the seasonality of suicides in the Athens Greater Area. Methods Data were collected for all recorded cases of suicides committed over a 5-year period (from 2008 to 2012) from the Athens Department of Forensic Medicine. Two sub-periods were studied in relation to the economic crisis: 2008-2010 and 2011-2012. Seasonality was estimated with the Poison regression variant of the circular normal distribution. Results Suicide seasonality appeared significant during 2008-2010 (relative risk, RR=1.36) and strengthened in the years 2011-2012 (RR=1.69), when the impact of the austerity measures was increasingly being felt by the Greek society. Regarding the latter sub-period, seasonality was established for males (RR=1.75), individuals aged 45 years or more (RR=1.75) and suicide by hanging (RR=1.96). Conclusion The economic crisis in Greece, especially in the period during its effects had a significant impact on the population's economic condition, seems to have strengthened the seasonality of suicides, while a noteworthy suicide risk of 96% was revealed for suicides by hanging (peak in early June).

Smooth Tests for Seasonality (평활 계절성 검정)

  • Lee, Geung-Hee
    • The Korean Journal of Applied Statistics
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    • v.24 no.1
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    • pp.45-59
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    • 2011
  • When using X-12-ARIMA for seasonal adjustment, we usually check whether the series has stable seasonality or not via D8 F-tests, Kruskal-Wallis test, and the spectral diagnostics. In this paper, we develop several smooth tests for seasonality based on a Fourier series to improve the spectral diagnostics of X-12-ARIMA. A simulation study is conducted to compare five smooth tests for seasonality and X-12-ARIMA's D8 F-test an Kruskal-Wallis test. The simulation study shows that smooth tests for seasonality performed well compared with D8 F-tests and a Kruskal-Wallis test.

The Influences of Changes in Macro-Environments on Hotel Sales: Cases of Deluxe Hotels in Gyeongju City (거시환경변화가 호텔매출액에 미치는 영향: 경주지역 특급호텔을 중심으로)

  • Son, Eun-Ho;Park, Duk-Byeong
    • The Korean Journal of Community Living Science
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    • v.19 no.4
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    • pp.697-706
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    • 2008
  • Generally, tourism environments are classified as macro or micro environments. Hotel revenues are influenced directly and indirectly by macro and micro environments. This study aims to examine the determinants of the change in macro-environments on hotel revenue. The explanatory variables in this research were wage, exchange rates (ER), consumer price index (CPI) and seasonality. The results of this study were as follows; The CPI and ER significantly affected the hotel food and beverage sales. The seasonality (summer and autumn) and wage significantly affected the hotel room sales. Wage and seasonality (summer and autumn) also significantly affected the total sale on the hotels.

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Angiotensin-Converting Enzyme(ACE) Gene Polymorphism and Seasonal Variation in Mood and Behavior (기분과 행동의 계절성 변동과 Angiotensin-Converting Enzyme(ACE) 유전자 다형성)

  • Jeon, Hye-Yeon;Lee, Heon-Jeong;Kang, Seung-Gul;Kim, Leen
    • Sleep Medicine and Psychophysiology
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    • v.14 no.1
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    • pp.26-32
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    • 2007
  • Objectives: Angiotensin-converting enzyme (ACE) gene polymorphism has been reported to be associated with depression and therapeutic outcome in depression. The purpose of this study was to determine whether ACE gene polymorphism is associated with seasonal variation in mood and behavior in a young Korean college student sample. Methods: 297 young Korean medical students were recruited in this study. All subjects were free of major medical and psychiatric problems. They were genotyped for the ACE gene polymorphism and evaluated the seasonal variation in mood and behavior by the Seasonality Pattern Assessment Questionnaire (SPAQ). Results: Global Seasonality Score (GSS) of SPAQ between three genotypes were not different. However, comparison of the group that showed seasonality of mood and behavior during winter with the group that did not showed seasonality indicated significant difference in genotype distribution ($x^2=6.79$, p=0.034). The D allele non-carrier (ll genotype) frequency was significantly higher in winter seasonality group than non-seasonality group ($x^2=6.59$, p=0.010;odds ratio [OR]=2.27, 95% confidence interval [CI] 1.20-4.28). Conclusion: These results suggest that the ACE gene polymorphism is related to winter-type seasonality in a Korean population.

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Test for the Presence of Seasonality in Time Series Models

  • Lee, Sung-Duck
    • Journal of the Korean Data and Information Science Society
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    • v.12 no.1
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    • pp.71-78
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    • 2001
  • Three test statistics are proposed for the presence of seasonality in multiplicative seasonal time series models. Further their common limiting distribution is derived under some assumptions.

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Spatio-Temporal Variability Analysis of Precipitation Data Through Circular Statistics (순환통계 분석을 통한 강수량 시계열의 시공간적 변동성 분석)

  • Kwon, Hyun-Han;Lee, Jeong-Ju
    • Journal of The Korean Society of Civil Engineers
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    • v.30 no.2B
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    • pp.191-198
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    • 2010
  • Assessing seasonality of precipitation is necessarily required to establish future plans and policies for water resources management. In this regard, a main objective of the study is to introduce an effective approach for assessing the seasonality of the precipitation and evaluate the seasonality through the proposed one. We have used circular statistics to characterize the seasonality on the precipitation in Korea. The circular statistics allow us to effectively assess changes in timing of the seasonality in detail. It was found that peak time on monthly rainfall occurred between end of June and early July in southern coastal area while the timing was delayed in northern part of Korea because of monsoon moving in from south to north. In case of annual daily peak precipitation, spatio-temporal variation of the peak time was increased. It is mainly because of geophysical effects, frequency and paths of typhoons. Finally, temporal variations on the timing of the peak seasons were evaluated through circular statistics by 30-year moving average data. The peak season in the Northen part of Korea (e.g. Seoul and Gangrung) has been moved back from early July to end of July while the peak season has been moved up from middle of July to early July in the Southern part of Korea (e.g. Busan and Mokpo). It seems that changes in seasonality are mostly modulated by variability in the east-asia monsoon system.

Traffic Seasonality aware Threshold Adjustment for Effective Source-side DoS Attack Detection

  • Nguyen, Giang-Truong;Nguyen, Van-Quyet;Nguyen, Sinh-Ngoc;Kim, Kyungbaek
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.5
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    • pp.2651-2673
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    • 2019
  • In order to detect Denial of Service (DoS) attacks, victim-side detection methods are used popularly such as static threshold-based method and machine learning-based method. However, as DoS attacking methods become more sophisticated, these methods reveal some natural disadvantages such as the late detection and the difficulty of tracing back attackers. Recently, in order to mitigate these drawbacks, source-side DoS detection methods have been researched. But, the source-side DoS detection methods have limitations if the volume of attack traffic is relatively very small and it is blended into legitimate traffic. Especially, with the subtle attack traffic, DoS detection methods may suffer from high false positive, considering legitimate traffic as attack traffic. In this paper, we propose an effective source-side DoS detection method with traffic seasonality aware adaptive threshold. The threshold of detecting DoS attack is adjusted adaptively to the fluctuated legitimate traffic in order to detect subtle attack traffic. Moreover, by understanding the seasonality of legitimate traffic, the threshold can be updated more carefully even though subtle attack happens and it helps to achieve low false positive. The extensive evaluation with the real traffic logs presents that the proposed method achieves very high detection rate over 90% with low false positive rate down to 5%.

A Study on Customer Satisfactions toward Hotel Restaurants (호텔레스토랑 이용고객의 메뉴 만족도에 관한 연구)

  • 강성일
    • Culinary science and hospitality research
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    • v.6 no.2
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    • pp.135-155
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    • 2000
  • The main purpose of this study is to investigate the factors affecting customer satisfactions toward the italic restaurants of hotels. Especially, the role of menu-related factors is elaborated. Based on the previous research findings, the following hypotheses were proposed and tested. First, customer evaluations of the factors related to the service of italic hotel restaurants wi11 show differences, depending upon demographics. The results found are as follows. Concerning the seasonality and variety of menu, customer evaluations differed by gender. Depending on age groups, customer evaluations differed for the communicative quality of menu, the restaurant atmosphere, the employee service level, and the food taste. By the type of occupations, there were differences in customer evaluations of the communicative quality of menu, the employee service level, and tie food taste. By the education levels, there were differences in the evaluations toward the seasonality and variety of menu, the restaurant atmosphere, the employee service level, and the food taste, Finally. concerning the restaurant atmosphere and the food taste, customer evaluations differed by their income levels. Second, the employee service level, the seasonality and variety of menu, the communicative quality of menu, the restaurant atmosphere, and the food taste are predicted to significantly affect customer satisfactions, My results were consistent with this prediction except for that the communicative quality of menu did not significantly affect customer satisfactions. Regarding the role of menu-related factors in customer satisfactions, my finding implies the importance of updating the menu, providing the variety and reflecting the seasonality. The more studies, however, should be needed to explore the various roles of menu-related factors in restaurant customer satisfactions.

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