• Journal of Chest Surgery
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• v.35 no.3
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• pp.209-216
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• 2002

Background: Valvular heart disease is still the most common health problem in Korea. By the end of the year 1999, there has been 94,586 cases of open heart surgery since the first case in 1958. Among them, 36,247 cases were acquired heart diseases and 20,704 of those had valvular heart disease. But there was no database system and every surgeon and physician had great difficulties in analysing and utilizing those tremendous medical resources. Therefore, we developed a valve registry database program and utilize it for risk factor analysis and so on. Material and Method: Personal computer-based multiuser database program was created using Microsoft AccessTM. That consisted of relational database structure with fine-tuned compact field variables and server-client architecture. Simple graphic user interface showed easy-to-use accessability and comprehensibility. User-oriented modular structure enabled easier modification through native AccessTM functions. Infinite application of query function aided users to extract, summarize, analyse and report the study result promptly. Result: About three-thousand cases of valve replacement procedure were performed in our hospital from 1968 to 1999. Total number of prosthesis replaced was 3,700. The numbers of cases for mitral, aortic and tricuspid valve replacement were 1600, 584, 76, respectively. Among them, 700 patients received prosthesis in more than two positions. Bioprosthesis or mechanical prosthesis were used in 1,280 and 1,500 patients respectively Redo valve replacements were performed in 460 patients totally and 40 patients annually Conclusion: Database program for registry of valvular heart disease was successfully developed and used in personal computer-based multiuser environment. This revealed promising results and perspectives in database management and utilization system.

• The Korean Journal of Nuclear Medicine Technology
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• v.18 no.1
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• pp.26-32
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• 2014

Purpose: As PET-MRI which has excellent soft tissue contrast is developed as integration system, many researches about clinical application are being conducted by comparing with existing display equipments. Because PET-MRI is actively used for head and neck cancer diagnosis in our hospital, lymph node metastasis before the patient's surgery was diagnosed and clinical usefulness of head and neck cancer PET-MRI scan was evaluated using pathological opinions and idiopathy surrounding tissue metastasis evaluation method. Materials and Methods: Targeting 100 head and neck cancer patients in SNUH from January to August in 2013. $^{18}F-FDG$ (5.18 MBq/kg) was intravenous injected and after 60 min of rest, torso (body TIM coil, Vibe-Dixon) and dedication (head-neck TIM coil, UTE, Dotarem injection) scans were conducted using $Bio-graph^{TM}$ mMR 3T (SIEMENS, Munich). Data were reorganized using iterative reconstruction and lymph node metastasis was read with Syngo.Via workstation. Subsequently, pathological observations and diagnosis before-and-after surgery were examined with integrated medical information system (EMR, best-care) in SNUH. Patient's diagnostic information was entered in each category of $2{\times}2$ decision matrix and was classified into true positive (TP), true negative (TN), false positive (FP) and false negative (FN). Based on these classified test results, sensitivity, specificity, accuracy, false negative and false positive rate were calculated. Results: In PET-MRI scan results of head and neck cancer patients, positive and negative cases of lymph node metastasis were 49 and 51 cases respectively and positive and negative lymph node metastasis through before-and-after surgery pathological results were 46 and 54 cases respectively. In both tests, TP which received positive lymph node metastasis were analyzed as 34 cases, FP which received positive lymph node metastasis in PET-MRI scan but received negative lymph node metastasis in pathological test were 4 cases, FN which received negative lymph node metastasis but received positive lymph node metastasis in pathological test was 1 case, and TN which received negative lymph node metastasis in both two tests were 50 cases. Based on these data, sensitivity in PET-MRI scan of head and neck cancer patient was identified to be 97.8%, specificity was 92.5%, accuracy was 95%, FN rate was 2.1% and FP rate was 7.00% respectively. Conclusion: PET-MRI which can apply the acquired functional information using high tissue contrast and various sequences was considered to be useful in determining the weapons before-and-after surgery in head and neck cancer diagnosis or in the evaluation of recurrence and remote detection of metastasis and uncertain idiopathy cervical lymph node metastasis. Additionally, clinical usefulness of PET-MRI through pathological test and integrated diagnosis and follow-up scan was considered to be sufficient as a standard diagnosis scan of head and neck cancer, and additional researches about the development of optimum MR sequence and clinical application are required.

• Progress in Medical Physics
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• v.13 no.4
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• pp.209-217
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• 2002

There have been many studies on the application of the reciprocal advantages of multimodality image to define accurate target volume in the Process of radiation treatment planning. For the proper use of the multimodality images, the registration works between different modality images should be performed in advance. In this study, we selected chamfer matching method and mutual information method as most popular methods in recent image registration studies considering the registration accuracy and clinical practicality. And the two registration methods were analyzed to deduce the optimal registration method according to the characteristics of images. Lung phantom of which multimodality images could be acquired was fabricated and CT, MRI and SPECT images of the phantom were used in this study. We developed the registration program which can perform the two registration methods properly and analyzed the registration results which were produced by the developed program in many different images' conditions. Although the overall accuracy of the registration in both chamfer matching method and mutual information method was acceptable, the registration errors in SPECT images which had lower resolution and in degraded images of which data were removed in some part were increased when chamfer matching method was applied. Especially in the case of degraded reference image, chamfer matching methods produce relatively large errors compared with mutual information method. Mutual information method can be estimated as more robust registration method than chamfer matching method in this study because it did not need the prerequisite works, the extraction of accurate contour points, and it produced more accurate registration results consistently regardless of the images' characteristics. The analysis of the registration methods in this study can be expected to provide useful information to the utilization of multimodality images in delineating target volume for radiation treatment planning and in many other clinical applications.

• The Journal of Korean Society for Radiation Therapy
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• v.21 no.1
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• pp.17-23
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• 2009

Purpose: In treating head and neck cancer, it is very important to irradiate uniform dose on the junction of the bilateral irradiation field of the upper head and neck and the anterior irradiation field of the lower neck. In order to improve dose distribution on the junction, this study attempted to correct non uniform dose resulting from under dose and over dose using the field-in-field technique in treating the anterior irradiation field of the lower neck and to apply the technique to the treatment of head and neck cancer through comparison with conventional treatment. Materials and Methods: In order to examine dose difference between the entry point and the exit point where beam diffusion happens in bilateral irradiation on the upper head and neck, we used an anthropomorphic phantom. Computer Tomography was applied to the anthropomorphic phantom, the dose of interest points was compared in radiation treatment planning, and it was corrected by calculating the dose ratio at the junction of the lower neck. Dose distribution on the junction of the irradiated field was determined by placing low-sensitivity film on the junction of the lower neck and measuring dose distribution on the conventional bilateral irradiation of the upper head and neck and on the anterior irradiation of the lower neck. In addition, using the field-in-field technique, which takes into account beam diffusion resulting from the bilateral irradiation of the upper head and neck, we measured difference in dose distribution on the junction in the anterior irradiation of the lower neck. In order to examine the dose at interest points on the junction, we compared and analyzed the change of dose at the interest points on the anthropomorphic phantom using a thermoluminescence dosimeter. Results: In case of dose sum with the bilateral irradiation of the upper head and neck when the field-in-field technique is applied to the junction of the lower neck in radiation treatment planning, The dose of under dose areas increased by 4.7~8.65%. The dose of over dose areas also decreased by 2.75~10.45%. Moreover, in the measurement using low-sensitivity film, the dose of under dose areas increased by 11.3%, and that of over dose areas decreased by 5.3%. In the measurement of interest point dose using a thermoluminescence dosimeter, the application of the field-in-field technique corrected under dose by minimum 7.5% and maximum 17.6%. Thus, with the technique, we could improve non.uniform dose distribution. Conclusion: By applying the field-in-field technique, which takes into account beam divergence in radiation treatment planning, we could reduce cold spots and hot spots through the correction of dose on the junction and, in particular, we could correct under dose at the entry point resulting from beam divergence. This study suggests that the clinical application of the field-in-field technique may reduce the risk of lymph node metastasis caused by under dose on the cervical lymph node.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.4
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• pp.733-742
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• 2000

Fundamental materialistic characterization and adsorption/neutralization behavior of waste egg shell for heavy metal ion have been studied for its application to wastewater treatment. To investigate the structural change and thermal decomposition characteristics of egg shell. X-ray diffraction and FT-IR analysis were conducted for egg shell treated at $105^{\circ}C$ and $700^{\circ}C$, respectively. For the result of FT-IR analysis, the sample treated at $700^{\circ}C$ showed a reduced C-O absorption band compared with that of egg shell treated at $105^{\circ}C$, which may be due to the $CO_2$ release. Unlike to the result of FT-IR analysis, the XRD patterns of egg shell were almost similar for the cases of $105^{\circ}C$ and $700^{\circ}C$ treatment. however, characteristic diffraction pattern of CaO was observed for $850^{\circ}C$ treatment, at which $CaCO_3$ is known to be completely converted to CaO. TGA/DTA analysis showed a slow decline in weight loss up to $600^{\circ}C$ and, for $600{\sim}800^{\circ}C$ range, the weight loss became drastic by reason of $CO_2$ discharge, which was accompanied by an appearance of major endothermic peak. The ratio of practical breakthrough time to ideal one, total transfer unit, and mass transfer coefficient were observed to be increased as the adsorption was progressed in a multiple-column fixed-bed reactor using egg shell as an adsorbent, which signified the distribution effect of mass transfer for continuous adsorption reaction. The neutralization effect of egg shell for several types of acidic wastewater made of different mineral acids was not much different from each other except for the case of $H_2SO_4$, for which the neutralization reaction was thought to be retarded by the formation of gypsum.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.4
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• pp.388-395
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• 2016

This paper explores the photocatalytic sensitivity of cement mortar incorporated with recycled $TiO_2$ from waste water sludge. Basically, $TiO_2$ cluster sank down slowly to the bottom of cement mortar specimen before setting and hardening process. This leads the mismatch of $TiO_2$ concentration on the top and the bottom faces of a specimen. This poorly dispersed $TiO_2$-cement mortar naturally exhibits poor NOx removal efficiency especially on the top of cementitious structure. In architectural engineering application such as building or housing structures, one can simply filp over from the bottom so that more $TiO_2$ concentrated surface can be placed outward into the air. However, in highway pavement case, this could not be applicable due to in-situ installation of concrete pavement. Hence, the dispersion of $TiO_2$ cluster inside the cementitous material is getting important issue onto road construction application. To elaborate this issue, according to our results, silica fume, high-ranged water reducer, viscosity agent, blast furnace slag were not enhanced much of dispersion characteristics of $TiO_2$ cluster. The combination of foaming agent and accelerator of hardening with viscosity agent and small grain size of fine aggregate may help the dispersion of $TiO_2$ inside cementitious materials. Even though the enhanced dispersion were applied to the specimen, NOx removal efficiency doest not change much for the top surface of the specimen. This concurrently affected by the presence of tiny air voids and the dispersion of $TiO_2$ in that these voids could easily adsorbed NOx gas with the aid of large surface area.

• The Korean Journal of Air & Space Law and Policy
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• v.26 no.1
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• pp.177-213
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• 2011

The purpose of this paper is to research on the liability and cases for space damage with reference to the space activity under the international space treaty and national space law of major countries. The United Nations has adopted two treaties relating to the liability for space damage as follows: the Outer Space Treaty of 1967 and the Liability Convention of 1972. Korea has enacted the Outer Space Damage Compensation Act of 2008 relating to the liability for space damages. The Outer Space Treaty of 1967 regulates the international responsibility for national activities in outer space, and the national tort liability for damage by space launching object. The Liability Convention of 1972 regulates the absolute liability by a launching state, the faulty liability by a launching state, the joint and several liability by a launching state, the person claiming for compensation, the claim method for compensation, the claim period of compensation, the claim for compensation and local remedy, the compensation amount for damage by a launching state, and the establishment of the Claims Commission. The Outer Space Damage Compensation Act of 2008 in Korea regulates the definition of space damage, the relation of the Outer Space Damage Compensation Act and the international treaty, the non-faulty liability for damage by a launching person, the concentration of liability and recourse by a launching person, the exclusion of application of the Product Liability Act, the limit amount of the liability for damage by a launching person, the cover of the liability insurance by a launching person, the measures and assistance by the government in case of occurring the space damage, and the exercise period of the claim right of compensation for damage. There are several cases with reference to the liability for damage caused by space accidents as follows: the Collision between Iridium 33 and Cosmos 2251, the Disintegration of Cosmos 954 over Canadian Territory, the Failure of Satellite Launching by Martin Marietta, and the Malfunctioning of Westar VI Satellite. In the disputes and lawsuits due to such space accidents, the problems relating to the liability for space damage have been settled by the application of absolute(strict) liability principle or faulty liability principle. The Liability Convention of 1972 should be improved as follows: the clear definition in respect of the claimer of compensation for damage, the measure in respect of the enforcement of decision by the Claims Commission. The Outer Space Damage Compensation Act of 2008 in Korea should be improved as follows: the inclusion of indirect damage into the definition of space damage, the change of the currency unit of the limit amount of liability for damage, the establishment of joint and several liability and recourse right for damage by space joint launching person, and the establishment of the Space Damage Compensation Review Commission. Korea has built the space center at Oinarodo, Goheung Province in June 2009. Korea has launched the first small launch vehicle KSLV-1 at the Naro Space Center in August 2009 and June 2010. In Korea, it will be the possibility to be occurred the problems relating to the international responsibility and the liability for space damage in the course of space activity. Accordingly the Korean government and launching organization should make the legal and systematic policy to cope with such problems.

• Management & Information Systems Review
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• v.36 no.3
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• pp.131-150
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• 2017

The purpose of this study is to observe the spread pattern of open source software (OSS) while establishing relations with surrounding actors during its operation period. In order to investigate the change pattern of participants in the OSS, we use a netnography on the basis of online data, which can trace the change patterns of the OSS depending on the passage of time. For this, the cases of three OSSs (e.g. jQuery, MooTools, and YUI), which are JavaScript frameworks, were compared, and the corresponding data were collected from the open application programming interface (API) of GitHub as well as blog and web searches. This research utilizes the translation process of the actor-network theory to categorize the stages of the change patterns on the OSS translation process. In the project commencement stage, we identified the type of three different OSS-related actors and defined associated relationships among them. The period, when a master commences a project at first, is refined through the course for the maintenance of source codes with persons concerned (i.e. project growth stage). Thereafter, the period when the users have gone through the observation and learning period by being exposed to promotion activities and codes usage respectively, and becoming to active participants, is regarded as the 'leap of participants' stage. Our results emphasize the importance of promotion processes in participants' selection of the OSS for participation and confirm the crowding-out effect that the rapid speed of OSS development retarded the emergence of participants.

• Sijohaknonchong
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• v.43
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• pp.41-66
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• 2015

A study on rhythm of a sijo was mostly conducted based on rhythm theory. As it is considered to define the rhythm of a formal sijo based on three verses, its significance has been recognized. However, if rhythm is understood to be superior to cadence or versification, it seems necessary to examine the rhythm of a sijo as a verse with a fixed form as well as a highly individual rhythm of each and every lyric poet, which is informal rhythm, in order to fully understand them. In this case, prosodie analysis by H. Meschonnic (1932~ 2009) can be a significant methodology. As this study gropes for a possibility to examine the rhythm of a sijo from a new perspective instead of existing rhythm theory through the application of H. Meschonnic's prosodie analysis, it can be regarded as an essay. Prosodie newly suggested by Meschonnic is referred to as linguistic organization of consonants and vowels and indication of their paradigm, and it conflicts the perspective that traditionally separates linguistic sound from meaning for dichotomous understanding. It is due to the fact that the organization of consonants and vowels is a unit that constitutes a complicated layer of significant sound and meaning. Accordingly, prosodie analysis that is irregularly and aperiodically distributed within poetic text can be considered as methodology aimed at explaining how a poem is integrated in terms of sound and semantics. The core of prosodie analysis is to examine how the phonologic system stands against the theme of a poem. It ultimately has the same way of establishing literary style of a poet as it is to explain a unique aesthetic structure that individual poems have and show distinct characteristics of linguistic use by a poet. Prior to application of the prosodie analysis to sijo in general, the study preparatorily conducted prosodie analysis on < Ouga > by Gosan Seon-do Yun.

• Journal of the Korea Institute of Building Construction
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• v.9 no.4
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• pp.55-61
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• 2009

Recently, the number of high-rise buildings being built in Korea by major construction companies for residential and commercial use has been increasing. When constructing a high-rise building, it is necessary to apply massive amounts of concrete to form a mat foundation that can withstand the huge load of the upper structure. However, it is of increasing concern that due to limitations in terms of the amount of placing equipment, available job-sites and systems for mass concrete placement in the construction field, it is not always possible to place a great quantity of concrete simultaneously in a large-scale mat foundation, and for this reason consistency between placement lift cannot be secured. In addition, a mat foundation Is likely to crack due to the stress caused by differences inhydration heat generation time. To derive a solution for these problems, this study provides test results of a hydration heat crack reduction method by applying placement lift change and setting time control with a super retarding agent for mass concrete in a large-scale mat foundation. Mock-up specimens with different mixtures and placement liftswere prepared at the job-site of a newly-constructed high-rise building. The test results show that slump flow of concrete before and after adding the super retarding agent somewhat Increases as the target retarding time gets longer, while the air content shows no great difference. The setting time was observed to be retarded as the target retarding time gets longer. As the target retarding time gets longer, compressive strength appears to be decreased at an early stage, but as time goes by, compressive strength gets higher, and the compressive strength at 28 days becomes equal or higher to that of plain concrete without a super retarding agent. For the effect of placement lift change and super retarding agent on the reduction of hydration heat, the application of 2 and 4 placement lifts and a super retarding agent makes it possible to secure consistency and reduce temperature difference between placement lifts, while also extending the time to reach peak temperature. This implies that the possibility of thermal crack induced by hydration heat is reduced. The best results are shown in the case of applying 4 placement lifts.