• Journal of the Korea Convergence Society
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• v.12 no.4
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• pp.249-258
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• 2021

Bitcoin prices have been soaring recently as investors flock to cryptocurrency exchanges. The purpose of this study is to predict the Bitcoin price using a deep learning model and analyze whether Bitcoin is profitable through investment strategy. LSTM is utilized as Bitcoin prediction model with nonlinearity and long-term memory and the profitability of MA cross-over strategy with predicted prices as input variables is analyzed. Investment performance of Bitcoin strategy using LSTM forecast prices from 2013 to 2021 showed return improvement of 5.5% and 46% more than market price MA cross-over strategy and benchmark Buy & Hold strategy, respectively. The results of this study, which expanded to recent data, supported the inefficiency of the cryptocurrency market, as did previous studies, and showed the feasibility of using the deep learning model for Bitcoin investors. In future research, it is necessary to develop optimal prediction models and improve the profitability of Bitcoin investment strategies through performance comparison of various deep learning models.

• The Southeast Asian review
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• v.20 no.3
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• pp.1-40
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• 2010

China and Southeast Asia share intimate relationships based on close spatial, temporal and human conditions. Thus, Southeast Asian studies in China boast of a long lineage of 'traditional', 'embryonic', 'closed' and 'opened' Southeast Asian studies. In the modern period the 'embryonic Southeast Asian studies,' professing conservative nationalism based on traditional Sino-centric perspectives, accumulated elementary knowledges on the history of Sino-Southeast Asian relations and Chinese communities in Southeast Asia. On the other hand, 'closed Southeast Asian studies' standing for radical Communism suffered from chronic stagnation. After the Reform and Opening, 'opened Southeast Asian studies' recorded impressive progress in the restoration and development of Southeast Asian studies. Nevertheless, 'opened Southeast Asian studies' are faced with some serious problems such as biased perspectives, traditional methods, and national subjects. Most of all, it is urgent to overcome Sino-centric perspectives on Southeast Asia. Despite the opening of Southeast Asian studies to the diverse methods of modern social sciences, descriptive studies prevail over analytical ones. Regardless of the diversification of subjects, national questions such as the overseas Chinese and cross-border nationalities are prone to excessive nationalism.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.2
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• pp.107-119
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• 2021

The cross-flow turbine is one of the most famous and widely used hydraulic power systems for a long time. The cross-flow turbine is especially popular in many countries and remote regions where off-grided because of its many benefits such as low cost, high efficiency at low head, simple structure, and easy maintenance. However, most modern turbines, including the cross-flow turbine, are unsuitable for the ultra-low head situation, known as less than 3m water head or zero head with over 0.5m/s flow velocity. In this study, we demonstrated a 20kW class inverted-type cross-flow turbine's performance. First, we reevaluated our previous studies and introduced how to design the inverted-type cross-flow turbine. Secondly, we fabricated the 20kW class inverted-type cross-flow turbine for the performance test. And then, we designed a testbed and installed the turbine system in the demonstration facility. In the end, we compare the demonstration with its previous CFD results. The comparing result shows that both CFD and real model fitted on guide vane angle at 10 degrees. At the demonstration, we achieved 42% turbine efficiency at runner speed 125 RPM.

• Proceedings of the Korean Fiber Society Conference
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• 1998.04a
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• pp.111-115
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• 1998

Fiber spinning is a continuous deformation process by which material is converted into a fiber. The melt spinning process was analyzed mainly by employing an asymptotic method of the so-called thin filament equations which formulates dynamics of spinning process by averaging over the cross-section of filament the set of fundamental equations. The method gives the approximate results for commonly used circular fiber spinning.(omitted)

• Journal of Chest Surgery
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• v.26 no.5
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• pp.343-348
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• 1993

Growth of suture line and anastomosis is required for long-term success after the tracheal and bronchial surgery in infant and pediatric patient. We used various suture materials in these cases, but the results were differ. To select the adequate suture material in tracheal surgery, we tried next. Tracheal anastomoses were performed in 150 Sprague Dawley rats, aged 4 to 8 [mean 5.8] weeks and weight 62 to 106[mean 83.6] gram, to compare polydioxanone[PDS] 7-0, polyglactin 910[Vicryl]7-0, and polypropylene [prolene] 8-0 suture materials. In 150 rats, only 29[20%] were lived over 300 days, and the weight was 250 to 320[mean 289.5]gram. Cross sectional area of the anastomoses and two or three tracheal rings below anastomosis site were measured under microscope, and calculated and compared as Hsieh`s equition. Cross-sectional area,anastomosis site/normal site 100, were 89.4 $\pm$ 5.34% in PDS group[n=9], 75.7 $\pm$ 6.06% in Vicrylgroup [n = 10], and 80.8$\pm$ 4.06% in Prolene group[n = 10]. Histopathologic studies were done for all autopsies or put in death around 300 days postoperatively. PDS absorblion was not seen 16 weeks after suture but disappeared over 24 weeks slide. Vicryl absorbtion was noted postoperative 8 to 16 weeks, with marked tissue reaction. Prolene showed least tissue reaction, but the suture material was persisted with regional fibrotic capsule.Causes of death were respiratory failure in 76 cases, tracheal rupture in 22 cases, hemorrhage, biting, starvation and etc. in 23 cases. With the brief review of literatures, we report the results.

• YAKHAK HOEJI
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• v.33 no.4
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• pp.229-236
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• 1989

Even though two different preparations are chemically equivalent, the variance of bioavailability differenciates the clinical effect of preparations, so that the preparations need to be evaluated by comparing bioavailability in vivo as well as chemical equivalence. In this study, bioequivalence tests of commercially available isoniazid tablets A, B, C and D (standard) were performed to give some guidelines to bioequivalence test. The bioavailability parameters obtained by drug administeration were statistically analyzed. Statistical evaluation of the data involved an analysis of variance for a cross over design. Cross over design was employed with 8 healthy volunteers. The results were within 20% difference of mean value in the AUC, Cmax, Tmax and amount of urinary excretion (Au) between standard and isoniazid tablets. The results of ANOVA showed no significant differences for 'group or sequence', but almost not for 'between subjects'. The tablet. A, B and D were within 20 min, but tablet C was within 50 min. Tablet A was biologically equivalent in the Au. tablet B biologically equivalent in the Au and AUC. Tablet C was biologically equivalent in the Au. The relationship between the dissolution rate and Au was significant.

• Journal of the Korean Society of Propulsion Engineers
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• v.13 no.2
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• pp.1-8
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• 2009

Present studies of these experiments was conducted to using water, over a range of cross-flow velocities from 42 to 136 m/s, with injection frequencies from 35.7 to 166.2 Hz. In cross-flow field, main parameters of liquid jet for secondary breakup were cross-flow drag rather than pressure pulse frequency. As oscillation of the periodic pressure, liquid jet was moved up and down. Also, a bulk of liquid jet puff was detected at upper field of liquid surface. Because of pressure pulsation frequency, an inclination of SMD for the structured layer was evanescent. Cross-sectional characteristics of SMD at downstream area were non-structured distributions. The tendency of volume flux value for various frequency of pressure pulse was same distribution. And volume flux was decreased when the frequency of pressure pulse increasing.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2008.10a
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• pp.287-300
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• 2008

Airflow distributions along tunnel and over the cross section are critical in selecting installation location of the velocity monitor to obtain the representative data for ventilation as well as fire safety systems. This paper aims at performing CFD and on-site studies to analyze the longitudinal and cross-sectional distributions of the air velocity in tunnels employing longitudinal and semi-transversal ventilation systems. This study can ultimately contribute to selecting the monitor type as well as the optimal installation locations in vehicle tunnel.

• Speech Sciences
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• v.8 no.1
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• pp.93-111
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• 2001

This study investigates the contribution of vocalic information following the release of an initial stop to the identification of the three-way stop contrast (aspirated, lax, and tense) in Korean. Recent studies showed that there is a strong interaction between consonant types and tone. The findings raise questions concerning Korean listeners' use of tonal (or vocalic F0) variation in differentiation initial tense, lax, and aspirated stops. The above issues are addressed in the present study using a cross-splicing methodology. The overall results show that low vocalic F0 provided the most salient information for lax stops; tense and aspirated stop identification depended on a combination of VOT, F0, and H1-H2 characteristics. The perceptual dominance of F0 over VOT for lax stops is consistent with the size of the F0 difference in utterance-initial position, as well as their prominent role in Korean intonational phonology.

• The Korean Journal of Pain
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• v.33 no.1
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• pp.90-96
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• 2020

Background: Parkinson's disease (PD) is a neurodegenerative disorder that is the second most common disorder after Alzheimer's disease. PD includes both "motor" and "non-motor" symptoms, one of which is pain. The aim of this study was to investigate the clinical characteristics of pain in patients with PD. Methods: This cross-sectional study included 250 patients diagnosed with PD, 70% of which had mild to moderate PD (stages 2/3 of Hoehn and Yahr scale). The average age was 67.4 years, and the average duration since PD diagnosis was 7.1 years. Relevant data collected from PD patients were obtained from their personal medical history. Results: The prevalence of pain was found to be high (82%), with most patients (79.2%) relating their pain to PD. Disease duration was correlated with the frequency of intense pain (R: 0.393; P < 0.05). PD pain is most frequently perceived as an electrical current (64%), and two pain varieties were most prevalent (2.60 ± 0.63). Our findings confirm links between pain, its evolution over time, its multi-modal character, the wide variety of symptoms of PD, and the female sex. Conclusions: Our results demonstrated that the pain felt by PD patients is mainly felt as an electrical current, which contrasts with other studies where the pain is described as burning and itching. Our classification is innovative because it is based on anatomy, whereas those of other authors were based on syndromes.