• Biomolecules & Therapeutics
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• v.19 no.1
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• pp.9-20
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• 2011

Repeated administration of addictive drugs causes cellular and molecular changes believed to be the mechanism of pro-addictive behaviors. Neuroadaptations also take place with repeated administration of amphetamine, methylphenidate and atomoxetine, drugs for Attention Deficit Hyperactivity Disorders (ADHD), and it is speculated that these changes may serve as markers to demonstrate the dependence liability of these therapies. In this review, we enumerate the neuroadaptive changes in molecules associated with neuronal signaling and plasticity, as well as neuronal morphology wrought by repeated administration of ADHD medications. We provide the current perspective on the dependence liability of these therapies, and also suggest of some factors that need to be considered in future investigations, so that what is drawn from animal studies would be better consolidated with those known clinically.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.5
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• pp.657-663
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• 2016

In this work, a novel silicon (Si) based floating body synaptic transistor (SFST) is studied to mimic the transition from short-term memory to long-term one in the biological system. The structure of the proposed SFST is based on an n-type metal-oxide-semiconductor field-effect transistor (MOSFET) with floating body and charge storage layer which provide the functions of short- and long-term memories, respectively. It has very similar characteristics with those of the biological memory system in the sense that the transition between short- and long-term memories is performed by the repetitive learning. Spike timing-dependent plasticity (STDP) characteristics are closely investigated for the SFST device. It has been found from the simulation results that the connectivity between pre- and post-synaptic neurons has strong dependence on the relative spike timing among electrical signals. In addition, the neuromorphic system having direct connection between the SFST devices and neuron circuits are designed.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1998.10a
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• pp.271-274
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• 1998

In this paper we examine long-term memory of the financial time-series by employing the R/S analysis, the Hurst exponent estimation, and the modified R/S analysis. The null hypothesis of white-noise is tested using the NYSE daily indexes from January 1966 to July 1998, and the results show that long-range dependence exists before the apparent structural break of the Black Monday in 1987.

• The Korean Journal of Applied Statistics
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• v.26 no.6
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• pp.987-998
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• 2013

This paper considers the statistical characteristics on the air quality (PM10) of Korea collected hourly in 2011. PM10 in Korea exhibits very strong correlations even for higher lags, namely, long range dependence. It is power-law tailed in marginal distribution, and generalized Pareto distribution successfully captures the thicker tail than log-normal distribution. However, slowly decaying autocorrelations may confuse practitioners since a non-stationary model (such as changes in mean) can produce spurious long term correlations for finite samples. We conduct a statistical testing procedure to distinguish two models and argue that the high persistency can be explained by non-stationary changes in mean model rather than long range dependent time series models.

• Korean Journal of Biological Psychiatry
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• v.1 no.1
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• pp.31-39
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• 1994

Anxiety and anxiety disorders are one of the most common and most serious psychiatric problems. Anti-anxiety drugs are one of the most effective treatment method for these problems. Benzodiazepines have various side-effects and the risk of overuse and abuse. Therefore, physicians should prescribe benzodiazepines carefully. However, they should not be discouraged from prescribing benzodiazepines when they have a knowledge of the pharmacological characteristics of these drugs and there is a clear indication for their use. Generally speaking, problems of benzodiazepine use such as dependence withdrawal symptoms, and cognitive impairment are more likely to occur with high dose, long-term use(more than 4 months), in geriatric patients and patients with a history of alcohol or other sustance abuse. But long-term or high-dose use can be jusified for patients with panic disorder of agoraphobia, and medically-ill patients with persistent anxiety that cannot be otherwise treated. In summary, there cannot be a general prescribing formulation for benzodiazepine use. Physician should always make their decision based on the individual patient's risk/benefit factors.

• Anxiety and mood
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• v.1 no.1
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• pp.31-36
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• 2005

Benzodiazepine (BDZ) has the possibilities of development of tolerance, withdrawal symptoms, and abuse/addiction, as well as chronically adverse effects. Although many guidelines have proposed the restricted prescription of them, their uses in many psychiatric areas as well as primary practice are still wide spread. So we tried to reappraise the clinical characteristics of BDZ and then to consider the appropriate use. Firstly, meta-analyses on long-term use of BDZ indicated the cognitive impairment, which could be improved after discontinuation of BDZ. Next, there have been some evidences that the long-term use of BDZ does not develop tolerance, contrary to our concern, and maintains good anxiolytic effects. Also, physiological dependence should be discriminated from abuse/addiction, assuming the reality that the risk of BDZ abuse/addiction is surely overestimated. These issues are discussed in detail.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.484.2-484.2
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• 2014

There are many efforts to improving the power conversion efficiencies (PCEs) of dye-sensitized solar cells (DSCs). Although DSCs have a low production cost, their low PCE and low thermal stability have limited commercial applications. This study describes the preparation of a novel multifunctional polymer gel electrolyte in which a cross-linking polymerization reaction is used to encapsulate $TiO_2$ nanoparticles toward improving the power conversion efficiency and long-term stability of a quasi-solid state DSC. A series of liquid junction dye-sensitized solar cells (DSCs) was fabricated based on polymer membrane encapsulated dye-sensitized $TiO_2$ nanoparticles, prepared using a surface-induced cross-linking polymerization reaction, to investigate the dependence of the solar cell performance on the encapsulating membrane layer thickness. The ion conductivity decreased as the membrane thickness increased; however, the long term-stability of the devices improved with increasing membrane thickness. Nanoparticles encapsulated in a thick membrane (ca. 37 nm), obtained using a 90 min polymerization time, exhibited excellent pore filling among $TiO_2$ particles. This nanoparticle layer was used to fabricate a thin-layered, quasi-solid state DSC. The thick membrane prevented short-circuit paths from forming between the counter and the $TiO_2$ electrode, thereby reducing the minimum necessary electrode separation distance. The quasi-solid state DSC yielded a high power conversion efficiency (7.6/8.1%) and excellent stability during heating at $65^{\circ}C$ over 30 days. These performance characteristics were superior to those obtained from a conventional DSC (7.5/3.5%) prepared using a $TiO_2$ active layer with the same thickness. The reduced electrode separation distance shortened the charge transport pathways, which compensated for the reduced ion conductivity in the polymer gel electrolyte. Excellent pore filling on the $TiO_2$ particles minimized the exposure of the dye to the liquid and reduced dye detachment.

• Journal of Korean Academy of Oral Health
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• v.42 no.4
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• pp.204-209
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• 2018

Objectives: This study was conducted to identify the demand and willingness to pay for oral hygiene services among elderly people with long-term care insurance. Methods: Our study was a cross-sectional analysis. Subjects comprised 126 elderly individuals from long-term home-care centers. A total of 28 centers were selected through convenience sampling from among 78 centers in ${\bigcirc}{\bigcirc}$. For analysis, semi-structured questionnaires that required about 20-30 minutes to complete were used. Analysis was performed using SPSS 23.0 software. Results: The overall demand for oral hygiene services was 44.4%, and willingness to pay was 31.0%. Thirty-three people (58.9%) of elderly those who have demand for an oral hygiene service were willing to pay for the service, and 64 people (91.4%) who did not have a demand were not willing to pay for it. Among those with partial dependence on brushing, 65.6% had demand for oral hygiene services and 50.0% were willing to pay costs. Among basic livelihood beneficiaries, 69.6% were willing to pay for oral hygiene services; general subjects and relievers were less willing to pay. Conclusions: The overall demand for oral hygiene services among elderly people was 44.4%, and the willingness to pay was as low as 31.0%.

• The Journal of Information Systems
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• v.23 no.1
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• pp.225-246
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• 2014

With the recent establishment of a ubiquitous environment and the paradigm shift to a smart society, the use of mobile devices, such as smart phones and tablet PCs, has become widespread. Thus, the trend is gradually shifting from using Web-based Instant Messenger to using Mobile-based Instant Messenger. Mobile Instant Messenger refers to a service that allows instant messaging as well as data sending and receiving between individuals with exclusive application programs(mobile Apps), which can be used in portable devices-such as smart phones-with wireless Internet access. Korea's portal sites, telecommunication companies, and even big companies have all rushed into the MIM market to join the competition. The reason so many companies are showing interest in the MIM business is because it is rising as a core platform to substitute portal sites in the mobile society, and MIM is perceived as the best means to attract and secure users. The intention to reuse or use continually was considered an important factor in maintaining a dominant position amidst such fierce competition, and consequently, most research thus far has reflected such thought. However, the frequent or long-term use of a system alone cannot indicate the definite success of the system, nor guarantee its dominant position in the market. On the contrary, MIM dependence, which goes beyond simple repetitive use and indicates a state where users actually or emotionally depend on a specific system, can better explain the user action. However, not much research has been conducted on dependence. The research results showed that lively message, concise message, message responsiveness, and social belonging significantly affected perceived usefulness. Message responsiveness, Link, and social belonging significantly affected flow. Flow significantly affected MIM dependence, and perceived usefulness did not affect MIM dependence. This study has proven that lively message, concise message, message responsiveness, Link, social belonging and perceived usefulness are important antecedents and mediating factors of MIM dependence. Moreover, this study is significant in that it explains the overall process of MIM dependence, and expands on the variety and scope of research that can be applied to MIM-related studies.

• The Journal of the Korea Contents Association
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• v.18 no.12
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• pp.62-74
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• 2018

This study was proposed to examine the mediating effect of basic psychological needs on how parenting attitude affect middle school students with over-dependence on smart phone. This study utilized 2017 survey research by National Information Society Agency (NIA), namely a long-term follow-up study of 901 people with over-dependence on internet and smart phone. This study showed two findings. First, over-dependence on smart phone had correlations with basic psychological needs- autonomy(r=-.22, p<.001) and competence(r=-.13, p<.001); with parenting attitude- positive parenting(r=-.21, p<.001) and negative parenting(r=.15, p<.001). Second, both parenting attitude and basic psychological needs had a causal relationship with over-dependence on smart phone. These results can provide a basis to reconsider social awareness on over-dependence on smart phone among middle school students. This study proposed few research directions for further study to prevent over-dependence on smart phone and to educate parents.