• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.08a
• /
• pp.311-312
• /
• 2010

The fabricated photovoltaic cells based on PIN heterojunctions, in this study, have a structure of ITO/poly(3, 4-ethylenedioxythiophene)-poly(styrenesulfonate)(PEDOT:PSS)/donor/donor:C60(10nm)/C60(35nm)/2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline(8nm)/Al(100nm). The thicknesses of an active layer(donor:C60), an electron transport layer(C60), and hole/exciton blocking layer(BCP) were fixed in the organic photovoltaic cells. We investigated the performance characteristics of the PIN organic photovoltaic cells with copper phthalocyanine(CuPc), tetracene and pentacene as a hole transport layer. Discussion on the photovoltaic cells with CuPc, tetracene and pentacene as a hole transport layer is focussed on the dependency of the power conversion efficiency on the deposition rate and thickness of hole transport layer. The device performance characteristics are elucidated from open-circuit-voltage(Voc), short-circuit-current(Jsc), fill factor(FF), and power conversion efficiency($\eta$). As the deposition rate of donor is reduced, the power conversion efficiency is enhanced by increased short-circuit-current(Jsc). The CuPc-based PIN photovoltaic cell has the limited dependency of power conversion efficiency on the thickness of hole transport layer because of relatively short exciton diffusion length. The photovoltaic cell using tetracene as a hole transport layer, which has relatively long diffusion length, has low efficiency. The maximum power conversion efficiencies of CuPc, tetracene, and pentacene-based photovoltaic cells with optimized deposition rate and thickness of hole transport layer have been achieved to 1.63%, 1.33% and 2.15%, respectively. The photovoltaic cell using pentacene as a hole transport layer showed the highest efficiency because of dramatically enhanced Jsc due to long diffusion length and strong thickness dependence.

• Research in Community and Public Health Nursing
• /
• v.20 no.2
• /
• pp.251-258
• /
• 2009

Purpose: The study aimed to compare characteristics associated with smoking and smoking cessation of those who had succeeded in smoking cessation. Methods: Data were collected from January to June, 2008. The subjects were 9,819 smokers who were registered at the smoking cessation clinic of public health centers in Incheon. Four characteristics (demographic, health promotion, smoking, smoking cessation) were compared between 6-week (short-term) and 6-month (long-term) success groups. Results: There was a significant difference between the 6-week and 6-month success groups for smoking cessation in demographic characteristics (gender, age, job, social security), health promotion (BMI, alcohol dependency, BP), smoking (first smoking age, smoking duration, expiration CO concentration, nicotine dependency), and smoking cessation (attempt to quit smoking, reason for smoking cessation, information source for registration). Conclusion: The group of short-term smoking cessation success was younger than the other. Also, short-term success group was of lower socioeconomic class than the other. The 6-month success group had a larger number of attempts to quit smoking. Therefore, smoking cessation policy should be focused more on younger people and those in lower socioeconomic status. These groups should be given advice on smoking cessation motives and more frequent counseling for smoking cessation.

• Annual Conference on Human and Language Technology
• /
• 2018.10a
• /
• pp.281-284
• /
• 2018

본 논문에서는 machine reading 분야에서 기존의 long short-term memory (LSTM) 모델이 가지는 문제점을 해결하는 새로운 네트워크를 제안하고자 한다. 기존의 LSTM 모델은 크게 두가지 제한점을 가지는데, 그 중 첫째는 forget gate로 인해 잊혀진 중요한 문맥 정보들이 복원될 수 있는 방법이 없다는 것이다. 자연어에서 과거의 문맥 정보에 따라 현재의 단어의 의미가 크게 좌지우지될 수 있으므로 올바른 문장의 이해를 위해 필요한 과거 문맥의 정보 유지는 필수적이다. 또 다른 문제는 자연어는 그 자체로 단어들 간의 복잡한 구조를 통해 문장이 이루어지는 반면 기존의 시계열 모델들은 단어들 간의 관계를 추론할 수 있는 직접적인 방법을 가지고 있지 않다는 것이다. 본 논문에서는 최근 딥 러닝 분야에서 널리 쓰이는 attention mechanism과 본 논문이 제안하는 restore gate를 결합한 네트워크를 통해 상기 문제를 해결하고자 한다. 본 논문의 실험에서는 기존의 다른 시계열 모델들과 비교를 통해 제안한 모델의 우수성을 확인하였다.

• 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 Information Processing Systems
• /
• v.15 no.5
• /
• pp.1231-1242
• /
• 2019

This paper presents a two-dimensional attention-based long short-memory (2D-ALSTM) model for stock index prediction, incorporating input attention and temporal attention mechanisms for weighting of important stocks and important time steps, respectively. The proposed model is designed to overcome the long-term dependency, stock selection, and stock volatility delay problems that negatively affect existing models. The 2D-ALSTM model is validated in a comparative experiment involving the two attention-based models multi-input LSTM (MI-LSTM) and dual-stage attention-based recurrent neural network (DARNN), with real stock data being used for training and evaluation. The model achieves superior performance compared to MI-LSTM and DARNN for stock index prediction on a KOSPI100 dataset.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.11a
• /
• pp.65-68
• /
• 2004

A lot of R&D efforts are being concentrated on the development of high performance HTS coated conductors(CC). Unlike the HTS Bi-2223 tape, a variety of processes have been tried to fabricate CC tapes. PLD and MOD are believed to be very effective methods, and high critical currents of long length CC tape have been reported. In this study, we prepared two kinds of YBCO CCs to evaluate electromagnetic property. One is YBCO tape deposited on IBAD template by PLD and the other is AMSC's MOD CC tape Critical current (Ic) in magnetic fields, its angular dependency, and n-value were measured and analyzed. Magnetic field property of Ic was appeared to be different due the fabrication process. MOD tape showed higher in-field property, n-value of both PLD and MOD tapes exponentially decreased with magnetic field. MOD tape showed higher n-value in whole magnetic fields.

• Journal of Digital Contents Society
• /
• v.5 no.1
• /
• pp.7-11
• /
• 2004

There are many problems that must solve to construct next generation high-speed communication network. Among these, item that must consider basically is characteristics analysis of traffic that nows to network Traffic characteristics of many Internet services that is offered present have shown that network traffic exhibits at a wide range of scals-self-similarity. Self-similarity is expressed by long term dependency, this is contradictory concept with Poisson model that have relativity short term dependency. Therefore, first of all, for design and dimensioning of next generation communication network, traffic model that are reflected burstiness and self-similarity is required. Here self-similarity can be characterized by Hurst parameter. In this paper, the calculation equation is derived considering queueing delay and self-similarity of data traffic art compared with simulation results.

• The Journal of Asian Finance, Economics and Business
• /
• v.8 no.5
• /
• pp.515-521
• /
• 2021

The popularity of Islamic financial instruments among Muslims is not surprising. The Islamic capital market is where sharia-compliant financial assets are transacted. It works parallel to the conventional market and helps investors find sharia-compliant investment opportunities. At a time of collective confusion when the COVID-19 epidemic is contributing to unprecedented change, this paper is keen to understand how attractive conventional and Islamic stock markets have been to investors recently. Second, this paper takes advantage of the time-scale decomposition property of the wavelet to simultaneously capture risk exposure and distinguish the risks faced by short- and long-term investors. To this end, this research conducted a two-step investigation of the daily closing equity market price indices for three Islamic stock markets and their conventional counterparts. Given that different financial decisions occur with greater or less frequency, the paper examines the connectedness of stock markets operating at heterogeneous rates and identifies the timescales using wavelet-DCC-GARCH analysis to take account of both the time and the frequency domains of stock market connectedness. The paper findings highlight the strong evidence of contagion that can be seen in nearly all conventional stock markets in the COVID-19 pandemic; they reach a high level of dependency in such health crises. Furthermore, Islamic stock markets prove to be a rich ground for global diversification.

• Journal of the Korea Society for Simulation
• /
• v.19 no.1
• /
• pp.103-111
• /
• 2010

Syntactic analysis is an important step in natural language processing. However, we cannot use the syntactic analyzer in Korean for low performance and without robustness. We propose new robust, high speed and high performance Korean syntactic analyzer using CRFs. We treat a parsing problem as a labeling problem. We use a cascaded chunking for Korean parsing. We label syntactic information to each Eojeol at each step using CRFs. CRFs use part-of-speech tag and Eojeol syntactic tag features. Our experimental results using 10-fold cross validation show significant improvement in the robustness, speed and performance of long Korea sentences.

• Journal of Korean Academy of Nursing
• /
• v.42 no.2
• /
• pp.236-247
• /
• 2012

Purpose: Purposes of this study were: evaluation of family burden of caring for elders who receive long term care services, and examination of differences in burden before and after the introduction of long term care service in Korea. Methods: Data were collected by questionnaires from 416 caregivers of elders who were registered with the Long Term Care Insurance Corporation in six cities. Data were collected in September, 2010 and analyzed using descriptive statistics, paired t-test, and ANOVA with the Scheffe test, and stepwise multiple regression. Results: Family burden decreased significantly after longterm care service was initiated. Subjective burden decreased from 2.93 to 2.69 (t=11.78, $p$<.001), and objective burden, from 3.40 to 3.10 (t=12.73, $p$<.001). Stepwise multiple regression analysis revealed that factors affecting subjective burden were family relations (F=13.60, $p$=.003), age (F=5.47, $p$=.019), job (F=6.98, $p$=.008), and education (F=4.59, $p$=.032), and that factors affecting objective burden were living together (F=17.66, $p$<.001), job (F=13.34, $p$=.003), monthly income (F=6.61, $p$=.010), and type of service (F=6.62, $p$=.010). Conclusion: The results of this first study to investigate caregiver burden after the Korean Long-term Care Insurance System was begun provide positive information for the development of strategies to decrease family burden in long term care.