• Sleep Medicine and Psychophysiology
• /
• v.10 no.1
• /
• pp.20-25
• /
• 2003

Many people suffer from chronic insomnia. Inappropriate sleep causes attention difficulties, decreased work efficiency, and increased traffic accidents and disasters. Evaluating the precise causes of insomnia prior to treatment is very important, because chronic insomnia can be a secondary symptom of other medical, psychiatric, and sleep disorders. Medication and behavior therapy are not exclusive of each other, and both treatments are beneficial to some patients, but currently many physicians and patients tend to be dependent only on medication. While long-term medication causes various degrees of dependency, tolerance, and withdrawal symptoms, behavior therapy has a stable effect over a long period. Behavior therapy is one of the most important treatment modalities for chronic insomnia. It shortens sleep latency, and decreases frequency of awakening during sleep. The rationale and practice of currently used behavior therapy and light therapy will be reviewed in this study.

• Journal of Applied Reliability
• /
• v.11 no.4
• /
• pp.387-398
• /
• 2011

$217Plus^{TM}$, a newly developed as a surrogate of the MIL-HDBK-217, may be widely applied for reliability predictions of electronic systems. In this study, we performed sensitivity study of the $217Plus^{TM}$ system model to various parameters. Specific attention was put to logistics model and its behavior has been examined in terms of non-component failure causes. We first briefly explained the $217Plus^{TM}$ methodology with system level failure rate evaluation. We then applied experimental designs with several failure causes as factors. We used an orthogonal array with three levels of each parameter. Our results indicate that cannot duplicate, induced, and wear-out causes have dominant effects on the system failures and design, parts, and system management have much less but a little strong effects. The results in this study not only figure out the behavior of the predicted failure rate as functions of failure causes but provide meaningful guidelines for practical applications.

• Sleep Medicine and Psychophysiology
• /
• v.3 no.2
• /
• pp.56-64
• /
• 1996

The sleeplessness in childhood is quite different from that in adulthood in terms of causes, developmental process, and treatment. Sleep behavior in childhood is strongly influenced by parental personality and familial and cultural background. In understanding and management of sleeplessness of children, it is especially important to understand the separation anxiety and the ways of its management in bedtime because bedtime routine with children one of separation process from parents. Co-sleeping, parental intervention, transional object and bedtime routines can be appeared in order to reduce the anxiety from bedtime separation. Causes of sleeplessness in infant and toddler are bad sleep-onset association, nocturnal drinking, colic, and food allergy. In preschool and school aged children, limit-setting sleep problem and fears and nightmare can be causes of sleeplessness. When good sleep environment and habits are established sound sleep and more mature personality can be developed.

• Proceedings of the Korean Reliability Society Conference
• /
• 2011.06a
• /
• pp.257-264
• /
• 2011

In this study, we performed sensitivity study of the $217Plus^{TM}$ system model to various parameters. Specific attention was put to logistics model and its behavior has been examined in terms of non-component failure causes. We first briefly explained the $217Plus^{TM}$ methodology with system level failure rate evaluation. We then applied experimental designs with several failure causes as factors. We used an orthogonal array with three levels of each parameter. Our results indicate that cannot duplicate, induced, and wear-out causes have dominant effects on the system failures and design, parts, and system management have much less but a little strong effects. The results in this study not only figure out the behavior of the predicted failure rate as functions of failure causes but provide meaningful guidelines for practical applications.

• Structural Engineering and Mechanics
• /
• v.54 no.6
• /
• pp.1111-1133
• /
• 2015

Rebar corrosion in concrete is one of the main causes of reduction of service life of reinforced concrete buildings. This paper presents the influence of rebar corrosion on the structural behavior of reinforced concrete (RC) buildings subjected to strong earthquake ground motion. Different levels of rebar corrosion scenarios were applied on a typical four story RC frame. The deteriorated conditions as a result of these scenarios include loss in cross-sectional area and loss of mechanical properties of the reinforcement bars, loss in bond strength, and loss in concrete strength and its modulus of elasticity. Dynamic analyses of the frame with different corrosion scenarios are performed with selected strong earthquake ground motion records. The influences of degradation in both concrete and reinforcement on structural behavior are investigated by comparing the various parameters of the frame under different corrosion scenarios with respect to each other. The results show that the progressive deterioration of the frame due to rebar corrosion causes serious structural behavior changes such as change in failure mode. The intensity, propagation time, and extensity of rebar corrosion have very important effects on the level of degradation of steel and concrete, as well as on the earthquake behavior of the structure.

• Journal of East-West Nursing Research
• /
• v.17 no.2
• /
• pp.125-131
• /
• 2011

Purpose: In an attempt to investigate causes of runaway impulse in male and female students with runaway impulse experience in high schools, this study was carried out. Methods: The subjects were 195 high school students in Gyeonggi and Incheon area. The data were collected by using the questionnaires. Results: To both male and female students, the main causes of runaway impulse were 'conflicts with parents', 'interference and excessive expectations of parents' and 'burden of study and grades'. In cases of youth with runaway experience by runaway impulse, the major causes of runaway impulse were 'want to have fun with friends' and 'conflicts with parents'. Also shelter and economic difficulties were obstacles that prevent a runaway despite runaway impulse to both male and female students. But in female, the fear and anxiety about runaway were higher barriers than those of male. Conclusion: From the above results, major causes of runaway impulses were relationships with parents, and burden of study. And barriers to prevent a runaway were shelter, economic difficulties to both male and female students.

• Korean System Dynamics Review
• /
• v.12 no.1
• /
• pp.5-37
• /
• 2011

This article aims to clarify what is the best investment behavior in Capital Intensive Industries(hereinafter CIIs) which show repeated business cycles. In CIIs, investments is centered in the period of upturns and goes beyond the adequate level because of the time that takes to completion of facilities. This over-investment causes oversupply and downturn, and in period of downturn, investments shrinks under the adequate level. The repeated change of over-investment and under-investment is the reason for the business cycles. In this article, a simulation model replicating the business cycles in CIIs was constructed and the effects of various investment strategies was tested. The results are as follows. First, the investment behavior following market condition causes the ongoing fluctuation of profits. Second, strategic increase in flexibility such as adjustment of facility utilization and shortening of facility construction time contributes to the increase in profit and stabilization of income. Third, in relation to market condition, the constant investment is more profitable in stagnated market and the counter-market investment is more profitable in growing market. In sum, it is desirable not to synchronize their investment with those of competitors.

• Sleep Medicine and Psychophysiology
• /
• v.2 no.2
• /
• pp.138-145
• /
• 1995

The causes of complicated chronic insomnia are very various and interact with vicious circle. Patient with this insomnia has generally a strong fear and frustration about failing to control of sleep and a deep mistrust toward doctor. To solve this complicated problems detailed history taking and sleep questionnaires are needed with objective polysomnography. Through these procedures, doctor should clarify causes of insomnia and explain them to patient in details and kindly. This process would be very helpful to restore the mistrustful relationship between patient and doctor and reduce patient's vague fear for insomnia. In treatment of complicated chronic insomnia, it is most important for patient to understand his problems and participate in the treatment schedule actively with assurance. Also doctor should encourage patient persistently not to be drop out. Most important factor for prognosis is patient's personality. Causes of complicated chronic insomnia are like these, overdose of hypnotics and sedatives, daily drinking alcohol with hypnotics, insomnia associated depression, delayed sleep phase syndrome, sleep state misperception, marked fear for insomnia, hyperarousal at bed, insomnia associated periodic leg movement and sleep apnea, chronic hypnotic insomnia, and immature personality. And possible treatments of these insomnias were discussed.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.23 no.1
• /
• pp.90-110
• /
• 1999

Understanding consumer complaining behaviors plays a key role in post-purchase satisfaction customer retention and long-term customer relationships. This research was conducted to empirically investigate 1) the taxonomy of complaining behavior 2) causes and types of clothing complaining behavior according to sex. The subjects compoed of 250 male and 358 female consuemrs. Data were colleted through questionnaires employing the critical incident methodology. The findings indicated that clothing complaining behavior was fitted well into Singh(1998)'s three-factor model(i. e. voice/private / third-party complaining behaviors) these factors explained 53% of the total variances 75.1% of male and 65.2% of female group complained of poor instruental performance. The types of complaining behaviors were no action negative word-of-mouth to friends and associates n order. Most dissatisfied consumers didn't assert positive consumer's right. Marketer should increase the accessibility of their complaint receiving mechanisms to passive customers.

• Journal of the Korean housing association
• /
• v.10 no.1
• /
• pp.21-35
• /
• 1999

The purposes of the study were: 1) to classify and describe causes of producing wasted furniture and household electric appliances by consumers, 2) to identify the influence of variables on causes of producing wasted furniture and household electric appliances and experience of consumer's recycling behaviors, and 3) to introduce the ways of activating recycling in wasted furniture and household electric appliances which suggested by consumers. 1,132 housewives living in Seoul, Sungnam, and Choongjoo were used as a final sample of the analysis. Data were collected using a self-administered survey. The result of the study indicated the major variable which affects producing wasted furniture and household electric appliances was the perception of recycling. Also, the level of consumers' recycling behavior in furniture and household electric appliances was very low and age and housing type were the major variables which affect consumers' recycling behavior. Finally, the implications and recommendations for consumers, enterprises, and society were suggested.