• Journal of the Korean Arthroscopy Society
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• v.3 no.2
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• pp.85-90
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• 1999

Purpose : The purpose of this study is to evaluate the clinical and histological results of the osteoarthritic patients who had second look arthroscopy after microfracture surgery. Materials and Methods : From Oct. 1997 to Dec. 1998, 46 patients, 48 knees were treated by microfracture technique. In the 22 patients, 24 knees, 'second-look' arthroscopies and biopsies were performed at 6 months following microfracture. Three patients were men and 19 patients were women. Average age of the patients were 58 years (range, 40-75 years). The average follow up period was 12 months(7-20 months). We analysed clinical results according to the nine-point scale. Also we observed type II collagen formation with immunohistochemical staining. Results : Clinical results were excellent in 83% and good in 17%. Among the 24 knees, more than 80% areas of chondral defect were covered with regenerated cartilage in 21 knees. Histologically, the regenerated tissue appears to be a hybrid of hyaline cartilage and fibrocartilage. Regenerated cartilage contains variable amount of type II collagen with immunohistochemical staining. Conclusion : Most of the patients had significant improvement clinically. 'Second-look' showed that the chondral defect areas were covered with newly grown grayish white tissue. Microfracture in the full thickness chondral defect provides and enriched environment for cartilaginous tissue regeneration.

• Korean Journal of Psychosomatic Medicine
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• v.7 no.2
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• pp.184-195
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• 1999

Objectives : As traumatic brain injury(TBI) leaves chronic sequelae in mind and body, the injured patients should rectify the meaning and object that they have pursued in their lives and set up a new purpose in life that they may make the rest of their lives meaningful. This study was designed to investigate the purpose and quality of life levels and the influence of demographic and clinical variables on the levels in the patients with TBI, and to be of some help to their rehabilitation. Methods : In order to assess the purpose in life(PIL) and the quality of life(QOL) levels, Purpose-in-Life Test, Sickness Impact Profile, Quality of Life Index, Head Injury Symptom Ckecklist, and Neurobehavioral Rating Scale were administered to the subjects. The subjects were thirty-two patients with TBI and the same numbered normal controls. The TBI group was composed of 16 to 65 year-aged patients who had received mild or severe TBI at least 12 months before, and the controls were siblings or friends of the patients whose age, sex, and educational level were similar to them. Results : 1) The PIL and QOL levels of the patients with TBI remained significantly lower than that of control group after their symptoms of injury were stabilized(p<.01, p<.01). 2) The mean PIL score of TBI group was $58.8{\pm}23.2$, which was to be regarded as the level of existential vacuum. 3) The PIL level of TBI group was significantly correlated with the QOL level(p <.01). 4) The subgroup with lower PIL level in patients with TBI has significantly higher rate of female than that with higher PIL(p<.05), the PIL level of female patients was significantly lower than that of male patients(p <.05). 5) The significant differences in PIL levels were not found, in which comparison was performed between each pair of subgroups of patients with TBI divided by severity of injury(mild vs severe), marital status(married vs unmarried), and occupational status prior to injury(employed vs unemployed). Conclusion : The PIL of patients with TBI still remained the level of existential vacuum after symptoms of sequelae had been stabilized, The QOL level was also extremely low, and as the PIL level was low the QOL was also low. The demographic and clinical variables except sex did not have influence on the PIL level in brain-injured patients. It is suggested that every patient should admit their mental and physical limitations caused by brain injury and revise their purpose in life for successful rehabilitation.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.11
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• pp.997-1006
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• 2009

Organic removal efficiency and methane production rate, a feasibility of power generation from biogas, and the optimum conditions for membrane operation were evaluated for the pilot scale (5 tons/day) two-phase anaerobic digestion coupled with ultra filtration (TPADUF) system fed with garbage leachate. The TPADUF system is consisted of a thermophilic acidogenic reactor, a mesophilic methanogenic reactor, and an UF membrane. When garbage leachate with 150 g/L of TCOD was fed to the TPADUF up to organic loading rate (OLR) of 11.1 g COD/L/d, the effluent TCOD was lower than 6 g/L and the average removal efficiencies of TCOD and SCOD were higher than 95%. The methane composition of the gas was 65%, and the methane yield was 39 $m^3/m^3$ garbage leachatefed, 260 $m^3$/tons $COD_{added}$, or 270 $m^3$/tons $COD_{removed}$, even there was some gas leak. The power production per consumed gas was 0.96 kWh/$m^3$ gas or 1.49 kWh/$m^3$ methane. This lower power production efficiency mainly due to the small capacity of gas engine (15 kW class). The membrane was operated at the average flux of 10 L/$m^2$/hr. When the flux decreased, washing with water and chemical (NaOCl) was conducted to restore the flux. In the TPADUF system, optimum pH could be maintained without alkali addition by recycling the membrane concentrate or mixed liquor of the methanogenic digester to the acidogenic reactor. Also, partial production of methane in the acidogenic reactor had a positive effect on lowering the OLR of the methanogenic reactor.

• Strategy21
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• s.30
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• pp.99-142
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• 2012

Withe increased North Korea's security threats, the South Korean navy has been faced with deteriorating security environment. While North Korea has increased asymmetric forces in the maritime and underwater with the development of nuclear weapons, and China and Japan have made a large investment in the buildup of naval forces, the power of the Pacific fleet of the US, a key ally is expected to be weakened. The biggest threat comes from China's intervention in case of full-scale war with North Korea, but low-density conflict issues are also serious problems. North Korea has violated the Armistice Agreement 2,660 times since the end of Korean War, among which the number of marine provocations reaches 1,430 times, and the tension over the NLL issue has been intensifying. With tension mounting between Korea and Japan over the Dokdo issue and conflict escalating with China over Ieo do Islet, the US Navy has confronted situation where it cannot fully concentrate on the security of the Korean peninsula, which leads to need for strengthening of South Korea's naval forces. Let's look at naval forces of neighboring countries. North Korea is threatening South Korean navy with its increased asymmetric forces, including submarines. China has achieved the remarkable development of naval forces since the promotion of 3-step plan to strengthen naval power from 1989, and it now retains highly modernized naval forces. Japan makes an investment in the construction of stat of the art warship every year. Since Japan's warship boasts of its advanced performance, Japan's Maritime Self Defense Force is evaluated the second most powerful behind the US Navy on the assumption that submarine power is not included in the naval forces. In this situation, naval power construction of South Korean navy should be done in phases, focusing on the followings; First, military strength to repel the energy warship quickly without any damage in case of battle with North Korea needs to be secured. Second, it is necessary to develop abilities to discourage the use of nuclear weapons of North Korea and attack its nuclear facilities in case of emergency. Third, construction of military power to suppress armed provocations from China and Japan is required. Based on the above naval power construction methods, the direction of power construction is suggested as follows. The sea fleet needs to build up its war potential to defeat the naval forces of North Korea quickly and participate in anti-submarine operations in response to North Korea's provocations. The task fleet should be composed of 3 task flotilla and retain the power to support the sea fleet and suppress the occurrence of maritime disputes with neighboring countries. In addition, it is necessary to expand submarine power, a high value power asset in preparation for establishment of submarine headquarters in 2015, develop anti-submarine helicopter and load SLAM-ER missile onto P-3C patrol aircraft. In case of maine corps, division class military force should be able to conduct landing operations. It takes more than 10 years to construct a new warship. Accordingly, it is necessary to establish plans for naval power construction carefully in consideration of reality and future. For the naval forces to safeguard maritime sovereignty and contribute to national security, the acquisition of a huge budget and buildup of military power is required. In this regard, enhancement of naval power can be achieved only through national, political and military understanding and agreement. It is necessary to let the nation know that modern naval forces with improved weapon system can serve as comprehensive armed forces to secure the command of the sea, perform defense of territory and territorial sky and attack the enemy's strategic facilities and budget inputted in the naval forces is the essential source for early end of the war and minimization of damage to the people. If the naval power construction is not realized, we can be faced with a national disgrace of usurpation of national sovereignty of 100 years ago. Accordingly, the strengthening of naval forces must be realized.

• Journal of Technology Innovation
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• v.24 no.1
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• pp.143-167
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• 2016

The purpose of this study is to analyze changes of innovation activities and their performance in pre-IPO and post-IPO of KOSDAQ IPO listed companies in medical and pharmaceutical fields, which require high R&D investment, from 2000 to 2005 in Korea. The innovation efficiencies of the IPO companies were measured before and after three years based on the DEA model. The financial data and patent information of the listed company during total 6 years, which were 3 years before IPO and 3 years after IPO, were collected. The main results of this research are as follows. First, it took an average 12.86 years until IPO in the start-up of the IPO companies in the pharmaceutical sector, and innovation was on average more active than the IPO before. R&D investment was higher than the IPO before, and the number of the applied patent during 3 years after IPO was 16.67 which was increased from 8.43 during 3 years before IPO. In addition, the average scope of technology of the IPO companies was expanded from 11 to 22 technology fields during previous 3 year and after 3 year each, and financial growth after IPO was lower than the previous IPO. Second, the financial performance of R&D investment and the performance of patent activity were weakened in the efficiency after the IPO, and the integrated performance from the patenting activities and the R&D investment was decreased after the IPO. Finally, the efficiency of the financial performance of the patenting activity was lower than the efficiency of the financial performance of the patent and R&D investment and patent activities under the R&D investment. In particular, the inefficiency of the firms' patenting activities performance after the IPO was caused by the decreasing return to scale, according to the results of this study. This results implicate that the expansion of R&D investments through the IPO had not lead to the financial performance of the market, and that the overall inefficiency since the IPO is due to the inefficiencies at the stage for the outcome of innovation activity rather than the output obtained through the R&D investments that appear to lead the performance of the market.

• The Journal of the Petrological Society of Korea
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• v.21 no.2
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• pp.235-247
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• 2012

Peridotite xenoliths hosted by alkali basalts from South Korea occur in Baengnyeong Island, Jeju Island, Boeun, Asan, Pyeongtaek and Ganseong areas. K-Ar whole-rock ages of the basaltic rocks range from 0.1 to 18.9 Ma. The peridotites are dominantly lherzolites and magnesian harzburgites, and the constituent minerals are Fo-rich olivine ($Fo_{88.4-92.0}$), En-rich orthopyroxene, Di-rich clinopyroxene, and Cr-rich spinel (Cr# = 7.8-53.6). Hydrous minerals, such as pargasite and phlogopite, or garnet have not been reported yet. The Korean peridotites are residues after variable degree of partial melting (up to 26%) and melt extraction from fertile MORB mantle. However, some samples (usually refractory harzburgites) exhibit metasomatic enrichment of the highly incompatible elements, such as LREE. Equilibration temperatures estimated using two-pyroxene geothermometry range from ca. 850 to $1050^{\circ}C$. Sr and Nd isotopic compositions in clinopyroxene separates from the Korean peridotites show trends between depleted MORB-like mantle (DMM) and bulk silicate earth (BSE), which can be explained by secondary metasomatic overprinting of a precursor time-integrated depleted mantle. The Korean peridotite clinopyroxenes define mixing trends between DMM and EM2 end members on Sr-Pb and Nd-Pb isotopic correlation diagrams, without any corresponding changes in the basement. This is contrary to what we observe in late Cenozoic intraplate volcanism in East Asia which shows two distinct mantle sources such as a DMM-EM1 array for NE China including Baengnyeong Island and a DMM-EM2 array for Southeast Asia including Jeju Island. This observation suggests the existence of large-scale two distinct mantle domains in the shallow asthenosphere beneath East Asia. The Re-Os model ages on Korean peridotites indicate that they have been isolated from convecting mantle between ca. 1.8 and 1.9 Ga.

• Korean Journal of Environment and Ecology
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• v.24 no.3
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• pp.249-257
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• 2010

The purpose of this paper is to weigh the possibility of endangered Jang-hang wetland at the estuary of Han River to be included on the Ramsar List of Wetlands of International Importance and come up with ways to manage the wetland depending on its biotope patterns. The target area is located between Gimpo bridge and Isanpo I.C. with about $2.7km^2$ area. Through the analysis of RIS(Information Sheet for Ramsar Wetlands), it was known that the wetland is located on the sedimentary topography and formed as a result of sediment at the estuary of the river owing to the concentration of rainfall during summer. The vegetation environment in the area is divided into brackish water and fresh water areas depending on salinity. Rhizosphere soil(RS) of the area was analyzed to be Silt loam while bottom RS to be Sand loam. The plant ecology was composed of 52 families 135 species and 11 varieties and 146 types. Among indigenous species found are Salix koreensis, Phragmites communis and Miscanthus sacchariflorus. The analyzed results of the actual vegetation showed that willow community accounts for 37% of the area and rice field is 13.5%. As for animal ecology, total of 62 species and 25,977 individual wild birds were observed. After comparing and analyzing the RIS we compiled with the Ramsar Site designation standards, it turns out that the Jang-hang wetland meets criteria 1(biographic region), criteria 2,3 and 4(species and ecological communities) and criteria 5 and 6(water birds). Thus, Jang-hang wetland is eligible for the Ramsar site. As a result of establishing and evaluating the biotope types for setting management areas, Jang-hang wetland has a total of 13 different types, and the grade I represents 75.4% of the area while the grade III 0.8% of the land status. We categorized four management zones for the wetland depending on the biotope patterns - preservation, restoration, use and buffer zones and suggested management methods for each zone.

• Journal of dental hygiene science
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• v.9 no.1
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• pp.83-89
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• 2009

About 380 dental hygienists who were working in public health centers in 2004 joined this study with questionnaires about the evaluation of job training programs regarding oral health care. The findings are as follows. 1. As for the general characteristics of subjects including location, age and career, the dental hygienists in Public Health Subcenters outnumbered the dental hygienists in Public Health Centers, as the former accounted for 61.1 and the latter 35.3 percent. And the dental hygienists in their 36~40s made up the largest age group. The group in their 11~15 years career revealed 48.4, over 16 years career 35.7, under 10 years career group 15.9 percent, respectively. 2. The portion of certification in the respondents was 28.9 percent, as compared to the 71.1percent of non-certification. The major reasons of non-certification were not-applying(44.6%), participation rejected (29.3%). 3. Freqently requested curriculums were school based oral health program(4.42, the highest by Linkert 5 point scale), followed by oral health education(4.41), public oral health services for the toddler and for the elderly(4.04), for the disabled(3.92), oral health planning evaluation(3.85) and oral health survey& investigation(3.69). The gap between Dental hygienists at Public Health Center and Public Health Subcenter was statistically significant different(p < 0.001) in oral health survey& investigation and oral health planning evaluation.

• Geophysics and Geophysical Exploration
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• v.9 no.1
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• pp.30-36
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• 2006

Japan's first pilot-scale $CO_2$ sequestration experiment has been conducted in Nagaoka, where 10400 t of $CO_2$ have been injected in an onshore aquifer at a depth of about 1100 m. Among various measurements conducted at the site for monitoring the injected $CO_2$, we conducted time-lapse crosswell seismic tomography between two observation wells to determine the distribution of $CO_2$ in the aquifer by the change of P-wave velocities. This paper reports the results of the crosswell seismic tomography conducted at the site. The crosswell seismic tomography measurements were carried out three times; once before the injection as a baseline survey, and twice during the injection as monitoring surveys. The velocity tomograms resulting from the monitoring surveys were compared to the baseline survey tomogram, and velocity difference tomograms were generated. The velocity difference tomograms showed that velocity had decreased in a part of the aquifer around the injection well, where the injected $CO_2$ was supposed to be distributed. We also found that the area in which velocity had decreased was expanding in the formation up-dip direction, as increasing amounts of $CO_2$ were injected. The maximum velocity reductions observed were 3.0% after 3200 t of $CO_2$ had been injected, and 3.5% after injection of 6200 t of $CO_2$. Although seismic tomography could map the area of velocity decrease due to $CO_2$ injection, we observed some contradictions with the results of time-lapse sonic logging, and with the geological condition of the cap rock. To investigate these contradictions, we conducted numerical experiments simulating the test site. As a result, we found that part of the velocity distribution displayed in the tomograms was affected by artefacts or ghosts caused by the source-receiver geometry for the crosswell tomography in this particular site. The maximum velocity decrease obtained by tomography (3.5%) was much smaller than that observed by sonic logging (more than 20%). The numerical experiment results showed that only 5.5% velocity reduction might be observed, although the model was given a 20% velocity reduction zone. Judging from this result, the actual velocity reduction can be more than 3.5%, the value we obtained from the field data reconstruction. Further studies are needed to obtain more accurate velocity values that are comparable to those obtained by sonic logging.

• Journal of the Korean Geotechnical Society
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• v.31 no.5
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• pp.5-21
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• 2015

An energy pile is a novel type of ground heat exchangers (GHEX's) which sets up heat exchange pipes inside a pile foundation, and allows to circulate a working fluid through the pipe for exchanging thermal energy with the surrounding ground stratum. Using existing foundation structure, the energy pile can function not only as a structural foundation but also as a GHEX. In this paper, six full-scale energy piles were constructed in a test bed with various configurations of the heat exchange pipe inside large-diameter cast-in-place piles, that is, three parallel U-type heat exchangers (5, 8 and 10 pairs), two coil type heat exchangers (with a 500 mm and 200 mm pitch), and one S-type heat exchanger. During constructing the energy piles, the constructability of each energy pile was evaluated with consideration of the installation time, the number of workers and any difficulty for installing. In order to evaluate the thermal performance of energy piles, the thermal performance tests were carried out by applying intermittent (8 hours operating-16 hours pause) artificial cooling operation to simulate a cooling load for commercial buildings. Through the thermal performance tests, the heat exchange rates of the six energy piles were evaluated in terms of the heat exchange amount normalized with the length of energy pile and/or the length of heat exchange pipe. Finally, the economic feasibility of energy pile was evaluated according to the various types of heat exchange pipe by calculating demanded expenses per 1 W/m based on the thermal performance test results along with the market value of heat exchange pipes and labor cost.