• 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.

• Journal of KIISE:Information Networking
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• v.30 no.3
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• pp.329-342
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• 2003

Most of the existing multicast routing protocols for ad-hoc networks do not take into account the efficiency of the protocol for the cases when there are large number of sources in the multicast group, resulting in either large overhead or poor data delivery ratio when the number of sources is large. In this paper, we propose a multicast routing protocol for ad-hoc networks, which particularly considers the scalability of the protocol in terms of the number of sources in the multicast groups. The proposed protocol designates a set of sources as the core sources. Each core source is a root of each tree that reaches all the destinations of the multicast group. The union of these trees constitutes the data delivery mesh, and each of the non-core sources finds the nearest core source in order to delegate its data delivery. For the efficient operation of the proposed protocol, it is important to have an appropriate number of core sources. Having too many of the core sources incurs excessive control and data packet overhead, whereas having too little of them results in a vulnerable and overloaded data delivery mesh. The data delivery mesh is optimally reconfigured through the periodic control message flooding from the core sources, whereas the connectivity of the mesh is maintained by a persistent local mesh recovery mechanism. The simulation results show that the proposed protocol achieves an efficient multicast communication with high data delivery ratio and low communication overhead compared with the other existing multicast routing protocols when there are multiple sources in the multicast group.

• Journal of Chest Surgery
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• v.31 no.5
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• pp.502-508
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• 1998

Proinflammatory cytokines such as tumor necrosis factor-$\alpha$(TNF-$\alpha$) have been implicated in myocardial and organ dysfunction associated with postperfusion syndrome. We tested the hypothesis that cytokine productions are depressed by preoperative cortiosteroid injection for cardiopulmonary bypass(CPB) and the postoperative courses will be better than without steriod pretreated cases. Cardiac surgery was performed in randomized blind fashion for 20 patients from June 1996 to September 1996. In the steroid group(n=10), corticosteroid(dexamethasone 1 mg/kg) was injected 1 hour before anesthetic induction, but in the control group(n=10), nothing was injected. Each of groups were sampled 11 times as scheduled for TNF-$\alpha$ bioassays. We have checked EKG, cardiac enzymes(CPK, LDH with isoenzyme), WBC count preoperative day, one day and three days after operation. Viatal signs were continuously monitored for three postoperaive days. In the postoperative period three patients in the control group had elevated body temperature and four patients had hypotension that required considerable intravenous fluid administration. But steroid injected patients showed normal body temperture and acceptable blood pressures without supportive treatment. CPK enzymes rose in control group higher than steroid group at postoperative 1st and 3rd day(CPK; 1122$\pm$465 vs 567$\pm$271, 864$\pm$42 vs 325$\pm$87), and CPK-MB enzymes rose in control group higher than steroid group at postoperative 1st day(106.4$\pm$115.1 vs 29.5$\pm$22.4)(P=0.02). Arterial tumor necrosis factor-$\alpha$ rose during cardiopulmonary bypass, peaking at 5 minutes before the end of aortic cross clamping(ACC-5min) in steroid group(11.9$\pm$4.7 pg/ml), and 5 minutes before the end of cardiopulmonary bypass(CPB-5min) in control group(22.3$\pm$6.8 pg/ml). The steroid pretreated patients had a shorter period of time in respirator suport time, ICU stay day, hospital admission day. We conclude that corticosteroid suppress cytokine production during and after cardiopulmonary bypass, and may improve the postoperative course through inhibition of reperfusion injury such as myocardial stunning and hemodynamic instability.

• Journal of Chest Surgery
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• v.34 no.6
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• pp.485-489
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• 2001

Background: The most important factor in preventing sternal complications is stable sternal approximation. We have tried to find the most effective sternal closure method by examining the incidence of sternal dehiscence with or without infection in patients with cardiac surgery through median sternotomy. Material and Method: This study was performed in 489 patients over 45 years of age with median sternotomy for open cardiac surgery. Simple closure with interrupted 6 wires was performed in 159 patients, figure-of-8 closure technique in 119, overlapping interrupted closure using 10 wires in 150, and combined closure technique of interrupted simple closure and figure-of-8 suture closure in 61. Two hundred thirty-four patients underwent valve and aortic operations and 213 patients coronary artery bypass surgery. Result: Sternal dehiscence with or without infection occurred in 12 (2.5 %) patients. The complication developed in 5 of 159 patients (3.1%) with six interrupted simple closure, in 4 of 119 patients (3.4%) with figure-of-8 closure, and in 3 of 150 patients (2.0%) with overlapping interrupted closure using 10 wires, but there was no complication in 61 patients with combined closure technique (relative risk for other closure techniques, p<0.05). There was no significant difference in the incidence of the sternal complication between valve and aortic operation group and coronary artery bypass group (3.0% vs 2.3%, not significant), but diabetes mellitus was a significant independent risk factor (odds ratio and multivariate analysis, p<0.05). Conclusion: The sternal closure technique that combines simple interrupted suture closure and figure-of-8 suture closure may be a more useful technique to enhance sternal stabilization compared to other closure techniques, such as simple interrupted closure, 8-figure closure, and overlapping interrupted closure.

• Journal of Chest Surgery
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• v.34 no.10
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• pp.787-791
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• 2001

Coronary artery aneurysm is a rare disorder. It is defined as abnormal dilatation of coronary artery with diameter exceeding 1.5 times the adjacent normal segments. The incidence of coronary aneurysm is 2.6% in Caucasians and 0.25% in Asians. Over half of the former were associated with atherosclerotic coronary artery disease. However, 70 percents of the latter were nonobstructive coronary artery aneurysms. Coronary artery fistula is a rare disorder. It has been identified in only 0.2% of routine cardiac angiographic studies conducted over a 10-year period. The clinical spectrums are various, asymtomatic, asymptomatic murmur, dyspnea on exertion, fatigue, and congestive heart failure. The right coronary artery (56%) and left coronary artery(36%) are mainly involved in the origin site of congenital coronary artery fistula. The draining site of fistula are right ventricle(39%), right atrium(33%), and pulmonary artery(20%) and so on. This 54 years-old woman had intermittent chest tightness and an abnormal mediastinal shadow on chest roentgenogram and chest C-T examination, which was diagnosed as a mediastinal mass such as teratoma. We performed the operation under left anterolateral thoracotomy for mass excision. However, we knew the mass had the pulsating arterial blood flow through a fine needle puncture of the mass and that it was attached to the left ventricle. We believed the excision of mass on beating heart would be very dangerous. Therefore, we closed the wound without excising the mass. After several days, we performed an echocardiography and coronary angiography, We knew it was cardiac tumor. Incidentally, the patient had a tortuous coronary fistula from the right coronary artery to pulmonary trunk. Using cardiopulmonary bypass with moderate systemic hypothermia, the mass was resected and the fistula was clipped with surgical clips. Pathology of the specimen was a giant coronary arterial aneurysm.

• Journal of Chest Surgery
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• v.40 no.1 s.270
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• pp.25-31
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• 2007

Background: Cerebral protection is one of the most important procedures during aortic arch surgery. We can minimize neurological complications through short period of total circulatory arrest and resuming of brain perfusion. We evaluated 11 patients who underwent arch replacement using antegrade brain perfusion via right axillary artery. Material and Method: Between July 2004 and July 2006, 11 patients (male 9, female 2) underwent aortic arch replacement with antegrade brain perfusion via right axillary artery. Preoperative diagnosis was listed; 5 type A aortic dissections (5/11, 45.5%), 5 aortic aneurysms (5/11, 45,5%) and 1 type A IMH (intramural hematoma, 1/11, 9%). The mean age at the time of operation was $60.3{\pm}12.8$ years. For antegrade brain perfusion, we performed right axillary artery cannulation in all patients. Retrograde brain perfusion was used briefly during total circulatory arrest. Result: The mean total circulatory arrest time was $31.1{\pm}16.9$ minutes and the mean retrograde brain perfusion time was $21{\pm}17.8$ minutes. Mean antegrade brain perfusion time was $77.9{\pm}17.5\;(43{\sim}101)$ minutes. We had neither operative mortality nor permanent neurological complications. Conclusion: By means of antegrade brain perfusion via right axillary artery, that could lead to decrease circulatory arrest time and minimize damages to severely atheromatous arch vessels, we can expect to reduce neurological complications after aortic arch replacement. Further investigation with iarge patient populations will be required.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.35 no.4
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• pp.110-125
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• 2017

The Cultural Properties Protection Act enacted 1962 to encourge culture level of people by preserving and using cultural properties introduced Cultural Properties Change Permission System in 2000 in order to cope with rather targeted range towards the national designated cultural properties, and introduced the Guidelines for Permission Standard regarding Construction Activities within the Historical Cultural Environment Preservation Area (2006) to complement permission process and targets, Notification of Minor Changes around the National Designated Cultural Properties (2008), etc and continuously put efforts to improve further ever since. Nonetheless, while it showed decrease in the number of process of change permission per individual cases after 2007, it began to increase again since 2010, reaching 1,554 cases by 2014 - about 29% of the cases being rejected or under observation, people living surrounding of cultural properties still experience inconveniences. This study has been carried out by creating integrated DB with total 7,403 cases of permission status from 5 Subcommittees (Building / Historic Sites / Natural Heritage / Modern Cultural Heritage / Important Folk Culture) in Cultural Heritage Committee that are related with changing status for the past 5 years (2010-2014), and by further analyzing 4,364 cases amongst, that were reviewed within historical and cultural environment preservation area - analyzed applying types and the characteristics, reviewed the improvement plans of operation guidelines for the Committee and acts of minor changes towards surroundings of the national designated cultural properties that regulate the status changing permission targets by categorizing analysis results and deriving implications. I hope that this will complement to the operational guidelines for the Committee, along with minor changing activities around cultural properties in short term, and to secure basic data for systematic improvement plans ie., for delegated works range from city/county/districts through our research. Also hope to improve administrative efficiency by reforming permission systems for building activities in historic cultural environment conservation area, and reduce inconvenience people might experience, by minimizing socioeconomic expense needed for the review.

• Journal of agriculture & life science
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• v.45 no.5
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• pp.105-113
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• 2011

This study was carried out to develop an automatic loading equipment that can load seedling trays on loading position of the seedling bed driving on enclosed-type rail installed for interconnecting each process of raising seedlings in plant factory. The experiment of transferring the seedling tray by monorail pusher was carried out to figure out the required transfer force and problems during push type device of transporting the plastic seedling trays, that has completed its sowing process, which are installed onto the board of different materials. From the results of this experiment, the loading equipment which can exactly load three of the seedling trays orderly on the loading position of the seedling bed was designed and made. When three sowed trays on every board are transferred by pusher with the speed is at 30 cm/s, the maximum peak transfer force with maximum overshooting at initial transient state and the maximum transfer force at stead state are were respectively 32.8 N, 29.4 N on rubber board, 29.7 N, 22.5 N on a wooden board, 26.9 N, 19.6 N on a acrylic board, and 27.6 N, 19.1 N on an iron board. Changes in the transfer force occurred its maximum at the moment when the pusher collided with the tray, after the collision gradually decreased until it became stable. When two or three trays placed it in order of widthwise are transferred, it is occurred the overlapping of the tray's external bracket. The developed automatic loading equipment with PLC controller did not make any operation error through 100 times of tests, its maximum seedling tray loading speed was 2 sec/tray and its maximum error of transferred location of the tray was 0.5 cm.

• (The)Study of the Eastern Classic
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• no.35
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• pp.415-445
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• 2009

A well-known historian, Ahn Jeong-Bok(Sun-Am, 1712~1791) was an expert on the country village community. He was a scholar of the "Nam-In" group, who was excluded from the corridors of power in those days. He kept on the move in various parts of country villages from his childhood. After settling down in Deok-Gok, Kwang-Ju, he stayed in the place devoting himself to the self-culture and the literary works. By his surrounding of environment, he had an academic interest in a concrete science rather than metaphysics and country villages rather than the central city. He considered the country villages as the link holding between a family and a country and had the conception of a confucianist community based on country villages, emphasizing the practice of confucianist virtues in everyday life. First of all, his confucianist community was the community based on country villages. He thought that the enlightenment was a matter of great importance for solving problems in country villages. As a solution to those problems, he suggested Hyang-Yak, the self-governed regulations of country villages. In his own village he made the self-governed rules Dong-Yak. When he was a provincial governer of Mok-Cheon, he put Hyang-Yak, the self-governed regulations of country villages in operation. It aimed for a kind of gentry-centric country village community. But Hyang-Yak was the regulations based on the agreement with each other, stressed the regard on the popular mind and the setting the pace of the gentry, and aimed for the harmony and order in a community through the practice of moral virtues in daily life. On the other hand, he had a conception of a country village's academic community. He thought of the development of educational intuitions as a pressing need of the enlightenment of country village. With young people he read confucianist books with comments in a village school, Seo-Jae. In his seventies, he made and put the self-regulations for academic community, Hak-Yak, in operations. It is considered that Hak-Yak was an example of his idea of academic community and his point of view on learning, which emphasized on the coincidence with reading and practice.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.789-797
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• 2021

The worldwide sizes of container ships are rapidly increasing. The container ship size in 2005, which was about 9,200 TEU has increased to 24,000 TEU in recent times. In addition to the increase in the sizes of the container ships, the arrivals/departures of large container vessels to/from Korea have also increased. Hence, the necessity for reviewing safe passage of such vessels is emphasized. In the present study, a 24,000 TEU container vessel was used as a model ship to calculate the under-keel clearance (UKC) at Gadeok Channel through which vessels must pass to arrive at Busan New Port, in accordance with the Korean Port and Fishing Port Design Standards and Commentary. In addition, the maximum allowable speed that meets UKC standards was calculated using various squat formulas, whose results were then compared with the current speed limit standards. The analysis results show that Busan New Port requires 10% marginal water depth, and the squat that meets this requirement is 0.95 m. Gadeok Channel requires 15% marginal water depth, and the squat that meets this requirement is 1.78 m; in this case, the maximum allowable speed is calculated as 15 kts. Busan New Port has set the speed limit as 12 kts, which is higher than the calculated 11 kts. Thus, speed limit reconsideration is required in terms of safety. However, the set speed limit for Gadeok Channel is 12 kts, which is lower than the calculated 15 kts. Thus, additional considerations may be provided to increase the speed limits for smooth navigational passage of vessels. The present study, however, is constrained by the fact that it reflects only a limited number of elements in the UKC and allowable speed calculations; therefore, more accurate UKC and safe speed values can be suggested based on extended studies to this research.