• The Journal of Asian Finance, Economics and Business
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• v.8 no.12
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• pp.1-7
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• 2021

The study examines the influence of COVID-19 on the stock market returns of Saudi Arabia. The data was analyzed through event study methodology using daily price data of Tadawul All Share Index (TASI). The study examines the behavior pattern of the Saudi Arabian stock market in different phases during the event period by selecting six-event windows with a range of 10 days. The results report a negative Abnormal Return (AR) of -0.003 on the event date, while the abnormal returns reversed the next day to 0.005 positively. The result of Cumulative Abnormal Return (CAR) is negative and significant at the 1 percent level in all the six-event windows starting from the event date to day 59 after the event for the TASI index. Even though the influence of the COVID-19 pandemic decreased after 30 days of the event date, it increased during the last ten days of the event window. The stock market volatility of Saudi Arabia increased during the post-event period compared to the pre-event period with a negative mean return of -0.326 and a greater standard deviation. In a conclusion, the study found a significant influence of the COVID-19 pandemic on the stock market returns of TASI.

• The Journal of Information Systems
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• v.31 no.3
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• pp.67-87
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• 2022

Purpose This study quantified companies' views on the COVID-19 pandemic with sentiment analysis of U.S. public companies' disclosures. It aims to provide timely insights to shareholders, investors, and consumers by analyzing and visualizing sentiment changes over time as well as similarities and differences by industry. Design/methodology/approach From more than fifty thousand Form 10-K and Form 10-Q published between 2020 and 2021, we extracted over one million texts related to the COVID-19 pandemic. Using the FinBERT language model fine-tuned in the finance domain, we conducted sentiment analysis of the texts, and we quantified and classified the data into positive, negative, and neutral. In addition, we illustrated the analysis results using various visualization techniques for easy understanding of information. Findings The analysis results indicated that U.S. public companies' overall sentiment changed over time as the COVID-19 pandemic progressed. Positive sentiment gradually increased, and negative sentiment tended to decrease over time, but there was no trend in neutral sentiment. When comparing sentiment by industry, the pattern of changes in the amount of positive and negative sentiment and time-series changes were similar in all industries, but differences among industries were shown in neutral sentiment.

• Journal of IKEEE
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• v.22 no.1
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• pp.127-135
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• 2018

This paper was studied the tri-band folded monopole antenna design with Mu-negative metamaterial unit cell, which operates at 700 MHz UHD broadcast band and 2.45 GHz/5 GHz WiFi band. The MNR metamaterial is fabricated by forming a capacitor on the backside of the antenna substrate and connecting it to the ground plane through a strip line and a via hole so that a single cell can operate in the MZR (Mu zero resonator). Through this, the resonance point can be controlled to resonate in the zero mode in 700 MHz band, and the bandwidth is improved. Experimental results show that the 10dB bandwidth and gain are 309 MHz (41.2%) and 5.298 dB at the first resonance point, and the 10dB bandwidth and gain at the second resonance point are 821.9 MHz (33.5%) and 2.7840 dB respectively. At the third resonance point, the gain and bandwidth were 1.1314 GHz (20.6%) and 2.9484 dB respectively. We confirmed that the resonance point with theoretical value is in agreement with experimental value. And the radiation pattern is generally omnidirectional, and it has been confirmed that the radiation pattern is good in both forward and backward directions at 0.75 GHz and 2.45 GHz, and has a radiation pattern with multiple lobes at 5.5 GHz.

• Journal of the Korean Geographical Society
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• v.38 no.5
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• pp.659-666
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• 2003

This study is a comparative analysis on the variabilities of spring precipitation and atmospheric circulations of 500hPa surfaces between dry years and wet years over the Korean Peninsula. The distribution of variabilities of precipitation in spring are different from month to month. In March, the pattern is west-high and east-low, in April, north-high and south-low, in May, east-high and west-low respectively. In the distribution of 500hPa geopotential height anomaly, dry years of March show west-high and east-low pattern in that negative anomaly zones are formed around the Korean Peninsula and western coast of the northern Pacific Ocean, and positive anomaly zones are formed in the inland of East Asia centered on Siberia. Consequently, the Korean Peninsula and neighboring regions experience dry season when the zonal flows are strong with the positive anomaly zones of zonal components. On the contrary in the wet years the westerlies are weak since the pattern is east-high and west-low in which the positive anomaly zones are formed over the Korean Peninsula centered on the Aleutian Islands and western coast of the northern Pacific Ocean and the negative anomaly zones are formed in the inland of East Asia centered on Tibet Plateau and Siberia. The dry years of April and May show north-high and south-low patterns in that negative anomaly zones are found from the center of the northern Pacific Ocean to the eastern coast of East Asia, and the positive anomaly zones are found in the center of East Asia extending from Aleutian Islands to Tibet Plateau. On the contrary, in the wet years the patterns show south-high and north-low. This study identified not only that there are contrary atmospheric circulation patterms between dry years and wet years over Korean Peninsua in spring, but also there are different atmosphric circulation patterns between early and late spring.

• Journal of Society of Preventive Korean Medicine
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• v.21 no.2
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• pp.23-34
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• 2017

Objectives : The aim of this study was to survey the present utilization of pattern identification(PI) by chronic disease and using PI system in the clinical field among Korean medicine doctors. Methods : This survey was conducted from Oct. 1 to Oct. 31, 2014 by face-to-face interview using structured questionnaire. The subjects were 400 Korean medicine doctors who worked in hospitals or clinics. The questionnaire consisted of whether use clinical experience by chronic disease and the utilization of PI, the utilization of PI systems, the PI utilization rate, and the correlation between utilization PI and so on. General elements consisted of sex, age, clinical experience, place of work, district and so on. Results and Conclusions : This study revealed that clinical experience by chronic disease used 24.0-90.8%. The most chronic diseases were chronic fatigue and chronic pain, and least disease was cancer. Experience of the utilization of PI among Korean medicine doctors who have clinical experience was 87.8-97.1%. Also, the most utilized disease was chronic gastritis & gastric ulcer, and least disease was dyslipidemia. In this case, the most common cases were using the one PI between the utilization of PI systems, and the utilization ratio of Visceral PI was the highest. Phi coefficient between the PI systems in chronic diseases divided into positive correlation and negative correlation. The correlation of dementia between Triple energizer PI and Six excesses PI was the highest at positive correlation, and the frequency of occurrence between Defense, Qi, Nutrient and Blood PI was the highest at positive correlation. The correlation of osteoarthropathy between Meridian and Collateral PI and Sasang Constitutional Medicine was the highest at negative correlation. Also the frequency of occurrence between Qi, Blood, Fluid and Humor PI and Sasang Constitutional Medicine was the highest at negative correlation. We hope that additional studies on systematic PI research of chronic disease which needed to be in korean oriental medicine and meet the needs of clinical consumer continue based on this study.

• Parasites, Hosts and Diseases
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• v.37 no.4
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• pp.249-256
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• 1999

A total of 198 sera from stray cats was assayed against Toxoplasma gondii antigen by western blot. Out of 198 sera assayed, 26 sera (13.1％) showed typical blot patterns against T gondii. When spotted by ELISA absorbance and indirect latex agglutination lest (ILAT) titer, all 26 cases were distributed over the cut-off value of ELISA whereas 24 cases (92.3％) were in the positive range of 1:32 or higher and 2 cases in negative range by ILAT. Among western blot negative 172 sera, 162 cases were negative in both ILAT and ELISA while 10 cases were reactive falsely such that three cases were ILAT positive with 1:32 titer and 9 cases were ELISA positive (2 cases overlapped). These 10 cases reacted peculiarly without typical binding pattern in Western blot. Sandwich-ELISA was performed with monoclonal antibodies (mAbs) of Tg563 (30 kDa, SAG 1), Tg505 (22 kDa, SAG2), Tg605 (43 kDa, SAG3), Tg556 (28 kDa, GRA2), Tg737 (32 kDa, GRA6). Tg695 (66 kDa, ROP2), Tg786 (42 kDa, ROP6), and Tg621 (32 kDa, anonymous but cytosolic) clone, respectively. All western blot-positive cases were in the positive range and negative cases in the negative range clearly. Among the 10 false reactive cases, 3 cases were in the positive range with one or more mAbs. All mAbs used in this study were confirmed to be specific to T. gondii infection as a standardized sandwich-ELISA to differentiate it from other pathogens.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.391-394
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• 2004

Change of paradigm of network attack technique was begun by fast extension of the latest Internet and new attack form is appearing. But, Most intrusion detection systems detect informed attack type because is doing based on misuse detection, and active correspondence is difficult in new attack. Therefore, to heighten detection rate for new attack pattern, visibilitys to apply human immunity mechanism are appearing. In this paper, we create self-file from normal behavior profile about network packet and embody self recognition algorithm to use self-nonself discrimination in the human immune system to detect anomaly behavior. Sense change because monitors self-file creating anomaly detector based on Negative Selection Algorithm that is self recognition algorithm's one and detects anomaly behavior. And we achieve simulation to use DARPA Network Dataset and verify effectiveness of algorithm through the anomaly detection rate.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.11
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• pp.69-77
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• 2004

An efficient board-level interconnect test algorithm is proposed considering both the ground bounce effect and the delay fault detection. The proposed algorithm is capable of IEEE 1149.1 interconnect test, negative ground bounce effect prevention, and also detects delay faults as well. The number of final test pattern set is not much different with the previous method, even our method enables to detect the delay faults in addition to the abilities the previous method guarantees.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.63-69
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• 1998

A new current controlled PWM technique with NPC structure is proposed in this paper. A current controlled PWM technique with neutral-point-clamped pulse-width modulation inverter composed of main switching devices which operates as switch for PWM and auxiliary switching devices to clamp the output terminal potential to the neutral point potential is described. The proposed current controller has a first and second current band. The switching pattern will be made by the first current band. According to the second current band, the output state of the switching pattern is changed into positive and negative state. This inverter output contains less harmonic content and lower switching frequency than that of conventional current controlled PWM technique at the same current limit. Two inverters are compared analytically and the performance is investigated by the computer simulation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05c
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• pp.152-155
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• 2002

During normal operation, partial discharge(PD) tests were performed using turbine generator analyzer(TGA) in high voltage motor. Epoxy-mica couplers are installed at motor terminal and analyzed PD signal using TGA. #A motor stator insulation is good because small partial discharges are detected PD pattern show that PD occurs in insulation. PD of #B motor is larger than that of #A motor and PD pattern show that positive PD larger than negative PD. It means that PD occurs between insulation and slot. And A phase PD magnitude of #B motor is large and high compare with any other phase. Therefore wedge, core and slot of #B motor need to check and repair.