• Journal of KIISE:Databases
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• v.30 no.4
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• pp.381-396
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• 2003

Subsequence matching is an operation that finds subsequences whose changing patterns are similar to a given query sequence from time-series databases. This paper points out the performance bottleneck in subsequence matching, and then proposes an effective method that improves the performance of entire subsequence matching significantly by resolving the performance bottleneck. First, we analyze the disk access and CPU processing times required during the index searching and post processing steps through preliminary experiments. Based on their results, we show that the post processing step is the main performance bottleneck in subsequence matching, and them claim that its optimization is a crucial issue overlooked in previous approaches. In order to resolve the performance bottleneck, we propose a simple but quite effective method that processes the post processing step in the optimal way. By rearranging the order of candidate subsequences to be compared with a query sequence, our method completely eliminates the redundancy of disk accesses and CPU processing occurred in the post processing step. We formally prove that our method is optimal and also does not incur any false dismissal. We show the effectiveness of our method by extensive experiments. The results show that our method achieves significant speed-up in the post processing step 3.91 to 9.42 times when using a data set of real-world stock sequences and 4.97 to 5.61 times when using data sets of a large volume of synthetic sequences. Also, the results show that our method reduces the weight of the post processing step in entire subsequence matching from about 90% to less than 70%. This implies that our method successfully resolves th performance bottleneck in subsequence matching. As a result, our method provides excellent performance in entire subsequence matching. The experimental results reveal that it is 3.05 to 5.60 times faster when using a data set of real-world stock sequences and 3.68 to 4.21 times faster when using data sets of a large volume of synthetic sequences compared with the previous one.

• Korean Journal of Heritage: History & Science
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• v.56 no.2
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• pp.12-26
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• 2023

Recently, 『Gyeongja(庚子)/Daetongryeok(大統曆)』(1600), a memorandum record of Yu Seong-ryong during the reign of King Seonjo(宣祖) of the Joseon Dynasty, was returned to Korea from Japan, and about 4,000 letters in cursive characters have been interpreted by Ro Seung-suk. The contents for 203 days written in the margin of 『Gyeongja(庚子)/Daetongryeok(大統曆)』 are mostly new, and are meaningful in understanding Yu's life and social association circumstances. There are daily routines of each day, contemporary figures, diseases and oriental medicine prescriptions. In particular, the combat record of Admiral Yi Sun-shin in 83 letters on the cover is very important to understand the situation in those days. It seems that the reason for writing the combat situations a year and a few months after Admiral Yi died in war was to honor his distinguished military service for a long time by King Seonjo's order according to the public opinion of the royal court. The record can be classified into two categories. First, Admiral Yi sighed when he heard about Yu's dismissal from the office in Gogeumdo, and was always alert with clear water on the boat after the Battle of Waekyo Castle. Second, he was killed by bullets shot by the enemy while directly encouraging battle, not listening to his men who tried to dissuade him from leading the naval battle at Noryang. This only contained contents of devoting his life desperately, which is an important proof of the theory of his death in war. It also contains nine methods for making liquor and another method that wasn't known to the public, and seems to include popular alcohol brewing methods or newly devised ones. In addition, there is a detail that Heo Jun, the author of 『Donguibogam』, introduced medicine to Yu, along with being unable to attend ancestral rites and relieving the poor written in red. There are also stories about Kang Hang(姜沆) returning to Korea after being captured by Japan and Lee Deok-hong(李德弘)'s son, who introduced Gugapseondo(龜甲船圖, the first picture of the Turtle Ship in Korea) to King Seonjo. In the light of the above, 『Gyeongja(庚子)/Daetongryeok(大統曆)』is an important historical record to empirically research not only figures related to Yu but also the circumstances of those days since it contains new facts that are not in the existing literature. In particular, the big accomplishment of this study is to correct the mistakenly known theory of Admiral Yi's suicide and to find out the new fact that Heo Jun provided medical information. In this respect, this book is expected to serve as a testament to the future study of the history and characters related to Yu in the mid-Joseon period.

• Tuberculosis and Respiratory Diseases
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• v.42 no.1
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• pp.58-66
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• 1995

Background: Acute interstitial pneumonia is a relatively rare form of interstitial pneumonia, since the vast majority of interstitial pneumonia have a more chronic course. It corresponds to the lesion described by Hamman and Rich, as Hamman-Rich disease in 1944. Another name in the clinical literature is accelerated interstitial pneumonia, idiopathic acute respiratory distress syndrome (idiopathic ARDS), and the organizing stage of diffuse alveolar damage. Acute interstitial pneumonia differs from chronic interstitial pneumonia by clinical and pathologic features. Clinically, this disease is characterized by a sudden onset and a rapid course, and reversible disease. Method and Purpose: Five cases of pathologically proven acute interstitial pneumonia were retrospectively studied to define the clinical, radiologic, and pathologic features. Results: 1) The five cases ranged in age from 31 to 77 years old. The onset of illness was acute in all patients, it began with viral-like prodrome 6~40 days prior to shortness of breath, and respiratory failure eventually developed in all patients. In 2 cases, generalized skin rash was accompanied with flu-like symptoms. Etiologic agent could not be identified in any case. 2) All patients had leukocytosis and severe hypoxemia. Pulmonary function test of 3 available cases shows restrictive ventilatory defect, and one survived patient(case 5) has a complete improvement of pulmonary function after dismissal. 3) Diffuse bilateral chest infiltrates were present radiologically. Theses were the ground-glass, consolidation, and reticular densities without honeycomb fibrosis in all patients. The pathologic abnormalities were the presence of increased numbers of macrophages and the formation of hyaline membranes within alveolar spaces. There was also interstitial thickening with edema, proliferation of immature fibroblast, and hyperplasia of type II pneumocyte. In the survived patient(case5), pathologic findings were relatively early stage of acute interstitial pneumonia, such as hyaline membrane with mild interstitial fibrosis. 4) Of the 5 patients, four patients died of respiratory failure 14~90 days after onset of first symptom, and one survived and recovered in symptoms, chest X ray, and pulmonary function test Conclusion: These results emphasize that acute interstitial pneumonia is clinically, radiologically, and pathologically distinct form of interstitial pneumonia and should be separated from the group of chronic interstitial pneumonia. Further studies will be needed to evaluate the pathogenesis and the treatment of acute interstitial pneumonia.

• The Korean Journal of Air & Space Law and Policy
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• v.33 no.1
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• pp.45-79
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• 2018

An increase of airplanes and military aircraft operation lead to significant demanding of residential claims by people who live in nearby airports and military bases due to noise, vibration and residential damages caused by aircraft operations. In recent years, a plaintiff has filed a lawsuit against the defendant, claiming the prohibition of using claimant's possessed land as a helicopter landing route, and the Daejeon High Court was in favour of the plaintiff. Although the Supreme Court later dismissed the Appeal Court decision, it is necessary to discuss the case of setting flight prohibited zone. In Japan, the airport noise lawsuits have been filed for a long time, mainly by environmental groups. Unlike the case that admitted residential damages caused by noise, the Yokohama District Court for the first time sentenced a judgment of the prohibition of the flight. This ruling was partially changed in the appellate court and some of the plaintiffs' claims were adopted. However, the Supreme Court of Japan finally rejected such decision from appeal and district courts. Atsugi Base is an army camp jointly used by the United States and Japan, and residents, live nearby, claim that they are suffering from mental damage such as physical abnormal, insomnia, and life disturbance because of the noise from airplane taking off and landing in the base. An administrative lawsuit was therefore preceded in the Yokohama District Court. The plaintiff requested the Japan Self-Defense Forces(hereinafter 'JSDF') and US military aircraft to be prohibited operating. The court firstly held the limitation of the flight operation from 10pm to 6am, except unavoidable circumstance. The case was appealed. The Supreme Court of Japan dismissed the original judgment on the flight claim of the JSDF aircraft, canceled the first judgment, and rejected the claims of the plaintiffs. The Supreme Court ruled that the exercise of the authority of the Minister of Defense is reasonable since the JSDF aircraft is operating public flight high zone. The court agreed that noise pollution is such an issue for the residents but there are countermeasures which can be taken by concerned parties. In Korea, the residents can sue against the United States or the Republic of Korea or the Ministry of National Defense for the prohibition of the aircraft operation. However, if they claim against US government regarding to the US military flight operation, the Korean court must issue a dismissal order as its jurisdiction exemption. According to the current case law, the Korean courts do not allow a claimant to appeal for the performance of obligation or an anonymous appeal against the Minister of National Defense for prohibiting flight of military aircraft. However, if the Administrative Appeals Act is amended and obligatory performance litigation is introduced, the claim to the Minister of National Defense can be permitted. In order to judge administrative case of the military aircraft operation, trade-off between interests of the residents and difficulties of the third parties should be measured in the court, if the Act is changed and such claims are granted. In this connection, the Minister of National Defense ought to prove and illuminate the profit from the military aircraft operation and it should be significantly greater than the benefits which neighboring residents will get from the prohibiting flight of military aircraft.

• KDI Journal of Economic Policy
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• v.34 no.3
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• pp.95-131
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• 2012

This study examines whether the executive turnover and the executive resignation during the term of office affect the performance of Korean state-owned enterprises. The executive turnover in the paper means the comprehensive change of the executives which includes the change after the term of office, the change after consecutive terms and the change during the term of office. The 'resignation' was named for the executive change during the term of office to distinguish from the executive turnover. The study scope of the paper is restrained to the comprehensive executive change itself irrespective of the term of office and the resignation during the term of office. Therefore the natural change of the executive after the term of office or the change after consecutive terms is not included in the study. Spontaneous resignation and forced resignation are not distinguished in the paper as the distinction between the two is not easy. The paper uses both the margin of return on asset and the margin of return on asset adjusted by industry as proxies of the performance of state-owned enterprises. The business nature of state-owned enterprise is considered in the study, the public nature not in it. The paper uses the five year (2004 to 2008) samples of 24 firms designated as public enterprises by Korean government. The analysis results are as follows. First, 45.1% of CEOs were changed a year during the sample period on the average. The average tenure period of CEOs was 2 years and 3 months and 49.9% among the changed CEOs resigned during the term of office. 41.6% of internal auditors were changed a year on the average. The average tenure period of internal auditors was 2 years and 2 months and 51.0% among the changed internal auditors resigned during the term of office. In case of outside directors, on average, 38.2% were changed a year. The average tenure period was 2 years and 7 months and 25.4% among the changed internal directors resigned during the term of office. These statistics show that numerous CEOs resigned before the finish of the three year term in office. Also, considering the tenure of an internal auditor and an outside director which diminished from 3 years to 2 years by an Act on the Management of Public Institutions (applied to the executives appointed since April 2007), it seems most internal auditors resigned during the term of office but most outside directors resigned after the end of the term. Secondly, There was no evidence that the executives were changed during the term of office because of the bad performance of prior year. On the other hand, contrary to the normal expectation, the performance of prior year of the state-owned enterprise where an outside director resigned during the term of office was significantly higher than that of other state-owned enterprises. It means that the clauses in related laws on the executive dismissal on grounds of bad performance did not work normally. Instead it can be said that the executive change was made by non-economic reasons such as a political motivation. Thirdly, the results from a fixed effect model show there were evidences that performance turned negatively when CEOs or outside directors resigned during the term of office. CEO's resignation during the term of office gave a significantly negative effect on the margin of return on asset. Outside director's resignation during the term of office lowered significantly the margin of return on asset adjusted by industry. These results suggest that the executive's change in Korean state-owned enterprises was not made by objective or economic standards such as management performance assessment and the negative effect on performance of the enterprises was had by the unfaithful obeyance of the legal executive term.