• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.8B
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• pp.691-700
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• 2006

Based on the destination IP address of incoming packets, the Internet routers determine next hops and forward packets toward final destinations through If address lookup. The bandwidth of communication links increases exponentially fast as well as the routing table size grows significant as the number of single host networks attached to the Internet increases. Since packets should be processed at wire-speed, the increased link speed reduces the processing time of a packet in routers, and hence more efficient and fast IP address lookup algorithms and architectures are required in the next generation routers. Most of the previous IP lookup schemes compare routing prefixes of shorter length first with a given input IP address. Since IP address lookup needs to find the most specific route of the given input, search continues until the longest matched prefix is found while it keeps remembering the current test matching prefix. In this paper, based on binary search on prefix length, we proposed a new IP address lookup algorithm which compares longer prefixes first. The proposed scheme is consisted of multiple tries with prefixes on leaves only. The trie composed of the longest prefixes is primarily searched whether there is a match with the given input. This processing is repeated for the trio of the next longer prefixes until there finds a match. Hence the proposed algorithm provides the fast search speed. The proposed algorithm also provides the incremental update of prefixes while the previous binary search on length scheme does not provide the incremental update because of pre-processing requirement. In this paper, we performed extensive simulations and showed the performance comparisons with related works.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.2
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• pp.153-165
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• 2014

Carbon dioxide capture and storage (CCS) technology is recognizing one of method responding the climate change with reduction of carbon dioxide in atmosphere. In Korea, due to its geological characteristics, sub-seabed geological $CO_2$ storage is regarded as more practical approach than on-land storage under the goal of its deployment. However, concerns on potential $CO_2$ leakage and relevant acidification issue in the marine environment can be an important subject in recently increasing sub-seabed geological $CO_2$ storage sites. In the present study effect data from literatures were collected in order to conduct an effect assessment of elevated $CO_2$ levels in marine environments using a species sensitivity distribution (SSD) various marine organisms such as microbe, crustacean, echinoderm, mollusc and fish. Results from literatures using domestic species were compared to those from foreign literatures to evaluate the reliability of the effect levels of each biological group and end-point. Ecological effect guidelines through estimating level of pH variation (${\delta}pH$) to adversely affect 5 and 50% of tested organisms, HC5 and HC50, were determined using SSD of marine organisms exposed to the $CO_2$-induced acidification. Estimated HC5 as ${\delta}pH$ of 0.137 can be used as only interim quality guideline possibly with adequate assessment factor. In the future, the current interim guideline as HC5 of ${\delta}pH$ in this study will look forward to compensate with supplement of ecotoxicological data reflecting various trophic levels and indigenous species.

• Economic and Environmental Geology
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• v.44 no.3
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• pp.229-238
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• 2011

S-wave, which provides lithology and pore fluid information, plays a key role in estimating gas-hydrate saturation. In general, P- and S-wave velocities increase in the presence of gas-hydrate and the P-wave velocity decreases in the presence of free gas under the gas-hydrate layer. Whereas there are very small changes, even slightly increases, in the S-wave velocity in the free gas layer because S-wave is not affected by the pore fluid when propagating in the free gas layer. To verify those velocity properties of the BSR (bottom-simulating reflector) depth in the gas-hydrate prospect area in the Ulleung Basin, P- and S-wave velocity profiles were derived from multi-component ocean-bottom seismic data which were acquired by Korea Institute of Geoscience and Mineral Resources (KIGAM) in May 2009. OBS (ocean-bottom seismometer) hydrophone component data were modeled and inverted first through the traveltime inversion method to derive P-wave velocity and depth model of survey area. 2-D multichannel stacked data were incorporated as an initial model. Two horizontal geophone component data, then, were polarization filtered and rotated to make radial component section. Traveltimes of main S-wave events were picked and used for forward modeling incorporating Poisson's ratio. This modeling provides S-wave profiles and Poisson's ratio profiles at every OBS site. The results shows that P-wave velocities in most OBS sites decrease beneath the BSR, whereas S-wave velocities slightly increase. Consequently, Poisson's ratio decreased strongly beneath the BSR indicating the presence of a free gas layer under the BSR.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.3
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• pp.223-234
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• 2016

This study aimed to the adsorption-removal of high- radioactive iodide (I) contained in the initially generated high-radioactive seawater waste (HSW), with the use of AgX (Ag-impregnated X zeolite). Adsorption of I by AgX (hereafter denoted as AgX-I adsorption) was increased by increasing the Ag-impregnated concentration in AgX, and its concentration was suitable at about 30 wt%. Because of AgCl precipitation by chloride ions contained in seawater waste, the leaching yields of Ag from AgX (Ag-impregnated concentration : about 30~35 wt%) was less than those in distilled water (< 1 mg/L). AgX-I adsorption was above 99% in the initial iodide concentration ($C_i$) of 0.01~10 mg/L at m/V (ratio of weight of adsorbent to solution volume)=2.5 g/L. This shows that efficient removal of I is possible. AgX-I adsorption was found to be more effective in distilled water than in seawater waste, and the influence of solution temperature was insignificant. Ag-I adsorption was better described by a Freundlich isotherm rather than a Langmuir isotherm. AgX-I adsorption kinetics can be expressed by a pseudo-second order rate equation. The adsorption rate constants ($k_2$) decreased by increasing $C_i$, and conversely increased by increasing the ratio of m/V and the solution temperature. This time, the activation energy of AgX-I adsorption was about 6.3 kJ/mol. This suggests that AgX-I adsorption is dominated by physical adsorption with weaker bonds. The evaluation of thermodynamic parameters (a negative Gibbs free energy and a positive Enthalpy) indicates that AgX-I adsorption is a spontaneous reaction (forward reaction), and an endothermic reaction indicating that higher temperatures are favored.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.2
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• pp.40-55
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• 2015

This study aims to evaluate the efficiency of the forest experience center for children led by the local community as experiential management for forest kindergarten education. For this, an importance and performance analysis was conducted on the forest experience center for children in Geumcheon-gu, which, of the 12 forest experience center for kids in Seoul, is the only one led by the local community. The questionnaire sheet for the analysis consisted of a total of 36 questions, 20 about place facility areas and 16 about management program areas(including 6 questions about the management led by the local community). The questionnaire survey was done during the period between January 12th and January 19th, 2015. The participants in the survey consisted of 15 forest education specialists and 50 teachers from 19 kindergartens who participated in the forest experience program. The number of questionnaire sheets collected and used for analysis was 13 copies and 43 copies, respectively. The mean values of importance and performance on the place facility areas were 4.07 and 3.78 for forest education specialists, and 4.16 and 3.84 for kindergarten teachers, respectively. The mean values of importance and performance regarding the management program area were 4.38 and 4.16 for forest education specialists, and 4.40 and 4.00 for kindergarten teachers, respectively. Both groups evaluated the place facility areas lower than the management program areas. They also evaluated performance lower than importance. In place facility area, 'accessibility', 'safety' and 'connectivity to forest trail', 'loose parts' and 'safety facilities' were required to 'keep up the good work', because they showed higher importance and performance in place facility areas. Even though most items of management as led by the local community including 'forest experience activity support' were evaluated as 'important', some, including 'effort for local revitalization', were evaluated as low in performance. However, as they were evaluated as higher in importance, if they pursue 'concentrate here', it is expected that they will be evaluated as higher in performance. In addition, considering that program areas including 'forest education specialist's role' are labeled under the management led by the local community, it reflected a positive evaluation. As a result, management led by the local community is efficient as a management system for the forest experience center for children in an experiential forest kindergarten education. Going forward, if this management system is durable in 'keep up the good work' and 'concentrate here', the forest experience center for children led by the local community will be an alternative for an effective experiential forest kindergarten education.

• Journal of the Korean Institute of Landscape Architecture
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• v.44 no.3
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• pp.25-36
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• 2016

As the first public park in Korea, birth place of the march first independence movement, and a representative space of leisure of old men, Tapgol Park contains diverse symbolisms and meanings. In 2000, Seoul authorities selected the symbolism of the March First independence movement, and carried forward the sacralization project of Tapgol Park. They eliminated facilities, including vending machines, and restricted most of the leisure activities in the park such as drinking singing dancing, speech, playing chess, writing calligraphy, etc., and loitering. Also, they changed the park's design into a less available space with green areas and switched wooden benches to granite stone. Since the project finished, a representative phenomenon was the elderly men's exodus to Jongmyo Park, where the restrictions were not strong as in Tapgol Park. As a result, the numbers of users in Tapgol Park decreased sharply. However, overcrowded(more than 3000) Jongmyo Park is also in the middle of a sacralization project now. According to an investigation including observation and in-depth interview, most of the elderly men who use the parks almost everyday were in the low economic class. They just visit the parks everyday and chat with their peers, gaining comfort from each other. These phenomena can be interpreted as a social exclusion in society, which made the elderly men move to another place. Meanwhile, although fifteen years has passed since the project was completed, many people still regard the Tapgol Park as a place for elderly men instead of the birth place of the March First Independence Movement. This study focused on such problems and vague place identity, which is neither a memorial place nor a public park. The study discovery the fact they missed the symbolism that Tapgol Park was the first urban park of Korea. Also, it stresses that the monumentality does not need to be sacred, reverent, or inflexible. With this point of view, this study discussed public aspect and everydayness, which are included in most of the urban parks. Finally, this study suggests Tapgol Park as an urban park that has an identity that embraces the condition of monumentality, everydayness, and publicness all together.

• Korean Journal of Heritage: History & Science
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• v.53 no.2
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• pp.270-285
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• 2020

This study examines the state of archeological research on Silla and Unified Silla conducted in North Korea and identifies its characteristics. In South Korea, most research has focused on prehistoric times in North Korea, and little research has been done on Silla and Unified Silla. Noting this, we attempted to examine the history of archaeological research in North Korea to provide foundations upon which to go forward. The research was examined in terms of general archaeological themes including tombs, fortresses, the capital city, earthenware, roof tiles, ornaments, weapons, and horse harnesses, and we identified four characteristics from the examination. First, Juche ideology had a great influence on interpretation of the unification of the three kingdoms. The Juche ideology was first proposed in 1955, and at the time, it was not fully established as an ideology but rather seen as constituting opposition to toadyism. Accordingly, the unification of the three kingdoms led by Silla was seen as amounting to collusion with foreign forces and was not acknowledged. A piece of evidence shows that this change took place around 1962. Second, an inclination to testify to the 'uniqueness' of the cultures of the three kingdoms is observed. The argument is that culture in the Korean peninsula has unique characteristics that set it apart from Chinese culture, and that the cultures of the three kingdoms share much in common. This inclination was not mentioned in research until the 1950s, and it can be seen as an effort to comply with Juche ideology and prove the principle of unity as stated in the national leader's instructions in the 1960s. Third, the influence of Goguryeo on the formation of Silla culture is emphasized. Related research explains that Baekje, Silla, and Gaya adopted the 'superior' culture of Goguryeo, and could establish 'uniqueness' of culture accordingly. It is claimed that an advanced Goguryeo culture was disseminated throughout Balhae and Unified Silla, and then to Goryeo, resulting in a true unification of the ethnic culture. Fourth, researchers in North Korea presume the Silla tombs and other relics to be far older than South Korean researchers' estimate. From a standpoint of highlighting the long history of Korea, they estimate the Silla Dynasty was founded in the early or mid-first century. Accordingly, archeological evidence that demonstrates the establishment of the state is dated as far back. Such an estimate is also indispensable in justifying the explanation that the chamber tombs of Goguryeo had a direct influence on Silla. These research characteristics which arose during the 1960s continue to be basic guidelines for North Korean researchers.

• Journal of Chest Surgery
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• v.38 no.2 s.247
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• pp.152-156
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• 2005

Background: Occlusive complications after arterial revascularization are difficult to treat and have high recurrence rate. This study was performed to establish an effective treatment modality and to evaluate the factors affecting the occlusive complications by analysis of clinical data. Material and Method: During the period of 5 years. 33 patients (55 reoperations) were studied at the Department of Thoracic and Cardiovascular Surgery, Pusan National University Hospital following 173 arterial revascularization surgeries. The clinical characteristics, operating methods, the time intervals of reoperation, used graft, and the results of treatment were evaluated retrospectively. Result: All the patients were men except one and the mean age was 63.5 years old. The mean time internal from first operation to reoperation was 11.9 months. The cause of arterial occlusive diseases were 28 atherosclerosis and 5 Burger's diseases, Associated diseases were Hypertension $(57.6\%)$, Diabetes mellitus $(33.3\%)$, heart failure $(18.2\%)$, and so on. The mean rate of reoperation was 1.67 times and the most common type of first operation was femoro-popliteal bypass grafting $(57.6\%)$. The graft that used revascularization surgery were 25 cases of PTFE and 6 case were Dacron. There was no statistical difference between two groups. The kinds of reoperations were thrombectomy in 20 cases, angioplasty 18 cases, re-bypass surgery in 13 cases, and lumbar sympathectomy in 4 cases. The results of reoperation were 15 cases of functional recovery, 7 cases of limb salvage, 5 cases of above-knee amputation. 3 cases of below-knee amputation and 3 deaths. Conclusion: The main cause of occlusive complications are occlusion of inflow or outflow artery. Treatments were different according to the first operation methods and graft used. The most frequent time of reoperation was within one year after the first operation. We believe that graft surveillance especially during the first year is very important factor in observing the patient. We can look forward to improving limb salvage rate to perform additional treatment such as radiological interventions and lumbar sympathectomy.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.874-882
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• 2017

As the interest on the air-pollution is gradually rising up at home and abroad, automotiv e and fuel researchers have been working on the exhaust emission reduction from vehicles through a lot of approaches, which consist of new engine design, innovative after-treatment systems, using clean (eco-friendly alternative) fuels and fuel quality improvement. This research has brought forward three main issues : evaporative, performance, air pollution. In addition, researcher studied the environment problems of the bio-ethanol, bio-butanol, bio-ETBE (Ethyl Tertiary Butyl Ether), MTBE (Methyl Tert iary Butyl Ether) fuel contained in the fuel as octane number improver. The researchers have many dat a about the health effects of ingestion of octane number improver. However, the data support the con clusion that octane number improver is a potential human carcinogen at high doses. Based on the bio-fuel and octane number improver types (bio-ethanol, bio-butanol, bio-ETBE, MTBE), this paper dis cussed the influence of gasoline fuel properties on the evaporative emission characteristics. Also, this p aper assessed the acceleration and power performance of gasoline vehicle for the bio-fuel property. As a result of the experiment, it was found that all the test fuels meet the domestic exhaust gas standards, and as a result of measurement of the vapor pressure of the test fuels, the bio - ethanol : 15 kPa and the biobutanol : 1.6 kPa. thus when manufacturing E3 fuel, Increasing the biobutanol content reduces evaporation gas and vapor pressure. In addition, Similar accelerating and powering performance was shown for the type of biofuel and when bio-butanol and bio-ethanol were compared accelerated perf ormance was improved by about 3.9% and vehicle power by 0.8%.

• Journal of the Korean Arthroscopy Society
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• v.8 no.2
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• pp.109-114
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• 2004

Purpose: To evaluate the clinical results and prove the effectiveness of arthroscopic capsular release in refractory adhesive capsulitis of shoulder. Materials and Methods: We preformed arthroscopic capsular refractory adhesive capsulitis that not responded by stretching execies for above 1 year. 21 cases were followed above 1 year and average follow up 3 years 1 months (1${\sim}$5 years). We checked VAS of pain, ADL of function. UCLA score which were evaluated at preoperation, postoperation 6 months, 1 years and last follow up period, and compared with each other at last follow up. Results: The VAS score improved average preoperative score 8 to average postoperative score1, the ADL score improved average preoperative score 7 to average postoperative score 26, the UCLA score improved average preoperative score 8 to average postoperative score 34. Forward elevation improved average preoperative 75 degrees to average postoperative 175 degrees, external rotatiion at side improved average preoperative 4 degrees to average postoperative 52 degrees, abduction improved average Preoperative 60 degrees to average postoperative 170 degrees, internal rotation at posterior improved preoperative thigh-lumbar 3 spinous process to postoperative 7th thoracic spinous process~9th thoracic spinous process. Conclusion: Arthroscopic capsular release in refractory adhesive capsulitis that non responsive to stretching exercise for above 1 year were effective treatment method.