• International Commerce and Information Review
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• v.10 no.3
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• pp.75-99
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• 2008

In the commercial transaction sellers use various sales strategies to increase profits, and this kind of sales strategies often causes damage to customers, it, moreover, is true that these examples happen in the electronic commercial market much more than in traditional one because of the characteristics if the electronic commerce. That's why people transact one another without face-to-face meeting in the electronic commerce market, so people one likely to fall for a trick to cheat and deceive. It's no doubt that the frequency of crime is higher than in face-to-face market. For that reason Cooling Off System, Consumer Compensation Insurance, Mutual Aid Association and Billing Payment Deposit System are in force the law related electronic commerce to protect customers' rights. In this paper it will be discussed about the periods of Cooling Off System and a received commodity notice of the Billing Payment Deposit System. Regarding these periods seven days for Cooling Off period and three days for a received commodity notice period are stipulated under the law of related electronic commerce to protect customers' rights, But each period has to be differentiated depending on each goods for this period to be reasonable and proper. Therefore in this study it will be focused on these facts and each period will be classified by the goods' purpose of purchase and quality.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.3
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• pp.173-183
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• 1993

Four wave gauges of pressure type were installed for about one month(1992. 2~3) for the analysis of wave agitations induced by the intrusion of long-period incident waves inside and outside of Donghae Harbor. Helmholtz natural period and second peak period of seiche in Donghae Harbor are found to be approximately 17.1 and 5.5 minutes from the spectral analysis of measured long-period wave data. Amplification ratio at Helmholtz natural period reaches about 10 which is five times as lagre as that of Youngil Bay, but wave amplitudes ill harbor were about 10 em during the measurement period which are relatively small.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.7
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• pp.131-137
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• 2020

The research investigates the impact of the lockdown period caused by the COVID-19 to the stock market of India. The study examines the extent of the influence of the lockdown on the Indian stock market and whether the market reaction would be the same in pre- and post-lockdown period caused by COVID-19. Market Model Event study methodology is used. A sample of 31 companies listed on Bombay Stock Exchange (BSE) are selected at random for the purpose of the study. The sample period taken for the study is 35 days (24 February-17 April, 2020). An event window of 35 days was taken with 20 days prior to the event and 15 days during the event. The event (t1) being the official announcement of the lockdown. The results indicate that the market reacted positively with significantly positive Average Abnormal Returns during the present lockdown period, and investors anticipated the lockdown and reacted positively, whereas in the pre-lockdown period investors panicked and it was reflected in negative AAR. The study finds evidence of a positive AR around the present lockdown period and confirms that lockdown had a positive impact on the stock market performance of stocks till the situation improves in the Indian context.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.2
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• pp.97-103
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• 2010

The four combustion stages in a diesel engine have close correlation among them. Especially, the ignition delay period has significant effect on the following combustion stage. And the period is also one of inevitable combustion processes in the diesel engine. For example, the diesel knocking is a well-known phenomenon due to the long ignition delay period. The interval of the ignition delay period is affected by the mixture formation process in the cylinder. However, in the case of the D.I. diesel engine, the available duration to make the mixture formation of air-fuel is very short. In addition, the means of the mixture formation mainly depends on the injection characteristics and properties of the fuel. It is difficult to make complete mixture. Therefore, an early stage of combustion is violent, which leads to the weakness of noise and vibration. In this study, using the visible engine, we measured the ignition delay period by photo sensor which detect occurrence of flame and presented the factors of the injection characteristics such as kinds of injection system, the injection pressure and the injection timing. The relation between the ignition delay period and cylinder pressure diagram which was concurrently obtained was also estimated.

• The Korean Journal of Food And Nutrition
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• v.30 no.5
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• pp.935-942
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• 2017

In the present study, kohlrabi-kimchi was prepared for assessment of changes in sensory qualities and measurement of changes in quality characteristics according to the storage period for the purpose of using kohlrabi as an ingredient of Kimchi. Examination of the physicochemical properties of kohlrabi-kimchi according to the storage period showed that the acidity increased steadily throughout the storage period, while soluble-solids content, pH and hardness decreased as the storage period elapsed. Meanwhile, the L value increased and then it decreased as the storage period elapsed, but, the a value increased and the b value gradually decreased after day 14 of storage. Reducing sugars increased up to day 10 of storage, and then they decreased slowly after day 15 of storage. Measurement of changes in lactic acid bacteria in kohlrabi-kimchi according to the storage period showed bacterial growth showing typical tendencies of Kimchi with a rapid increase on day 5 of storage and a decrease thereafter. Assessment of sensory qualities of kohlrabi-kimchi according to the storage period showed that the highest scores for appearance and sourness, odor, texture, and overall scores were obtained on day 15 of storage. Based on the above results, it was determined that the optimal maturity period of kohlrabi-kimchi is day 15 of storage.

• Journal of the Institute of Convergence Signal Processing
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• v.7 no.4
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• pp.178-183
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• 2006

As a lot of researches on the speech signal processing are performed due to the recent rapid development of the information-communication technology. the pitch period is used as an important element to various speech signal application fields such as the speech recognition. speaker identification. speech analysis. or speech synthesis. A variety of algorithms for the time and the frequency domains related with such pitch period detection have been suggested. One of the pitch detection algorithms for the time domain. AMDF (average magnitude difference function) uses distance between two valley points as the calculated pitch period. However, it has a problem that the algorithm becomes complex in selecting the valley points for the pitch period detection. Therefore, in this paper we proposed the modified AMDF(M-AMDF) algorithm which recognizes the entire minimum valley points as the pitch period of the speech signal by using the rotation transform of AMDF. In addition, a threshold is set to the beginning portion of speech so that it can be used as the selection criteria for the pitch period. Moreover the proposed algorithm is compared with the conventional ones by means of the simulation, and presents better properties than others.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.6
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• pp.111-117
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• 2005

The period of a recent streamcipher proposal Edon80 is analyzed. The designers of Edon80 had projected a period of $2^{103}$ Even though this could indeed be the average keystream Period, we show that for a randomly chosen key-IV pair, there exists a non-dismissible probability that the produced keystream will be of relatively short period. More explicitly, a keystream of period. $2^{55}$ may appear with probability $2^{-71}$, and one can show the existence of at least one key-lV pair producing a period $2^{11}$ keystream.

• Journal for History of Mathematics
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• v.37 no.3
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• pp.41-57
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• 2024

In this study, the life of Lee Kyo Seung(1868~1951), the author of SinJeongSanSul(1~3), is traced in outline. He worked as a teacher at a government elementary school from 1895 to 1906. He contributed to elementary education as one of the first government elementary school teachers in the period of the Great Han Empire. During this period, he wrote SinJeongSanSul(1~3). He contributed to secondary mathematics education as a professor at Sungyunkwan for three years from November 1908, and as a mathematics teacher at the YMCA Academy from 1906 to 1916 in the period of the Great Han Empire and early Japanese colonial period. During this period, he wrote two different secondary school mathematics textbooks. During the Great Han Empire and early Japanese colonial period, he was a pioneering textbook author and mathematics teacher. So he can be evaluated as one of the important persons in the history of mathematics education in Korea.

• Journal of Korean Neurosurgical Society
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• v.30 no.5
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• pp.581-585
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• 2001

Objectives : Criteria for evaluating the results of treating low back pain vary widely. We examined the methods measuring the outcome in the papers of Journal of Korean Neurosurgical Society. Methods : We selected all published articles describing the methods measuring the outcome of low back pain in the journal. They were classified into 3 periods such as period 1 for volume 1-20, 2 for volume 21-25, and 3 for volume 26-28. Results : There are 25 articles in period 1, 44 in period 2, and 30 in period 3. The outcome was classified into 0 to 5 classes by more than 15 different methods. Although the terms and descriptive criteria differ, 4 classes were the most common classification, being 16 in period 1, 39 in period 2, and 19 in period 3. The outcome was usually measured by authors' own method in period 1. In period 2, criteria by Gill et al was most commonly used along with many different criteria. Criteria by Prolo et al became a common method in period 3. Conclusion : Varying methods compromised comparative analyses of outcome. A more simple and universally applicable criteria is necessary to facilitate comparisons among various methods of treatment.

• Journal of Korean Library and Information Science Society
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• v.38 no.2
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• pp.147-164
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• 2007

The objective of this study is to examine the correlation of reading quantities in different developmental phases and various media(magazines, books, comic books). I surveyed reading quantifies in developmental periods, by questionnaires. As a methodology of empirical study, data was collected from 187 students at the Chonbuk National University. Statistical techniques of a Pearson Correlation Test were employed according to my hypotheses. The results of this survey are as follows: 1) reading quantities of general book of specific period is correlated with general book reading quantities of specific period. 2) reading quantities of magazine of specific period is correlated with magazine reading quantities of other period 3) reading quantities of comic book of specific period is correlated with comic book reading quantities of other period 4) correlation among reading quantity of middle school period and high school period is high.