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Market Structure Analysis of Automobile Market in U.S.A (미국자동차시장의 구조분석)

  • Choi, In-Hye;Lee, Seo-Goo;Yi, Seong-Keun
    • Journal of Global Scholars of Marketing Science
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    • v.18 no.1
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    • pp.141-156
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    • 2008
  • Market structure analysis is a very useful tool to analyze the competition boundary of the brand or the company. But most of the studies in market structure analysis, the concern lies in nondurable goods such as candies, soft drink and etc. because of the their availability of the data. In the field of durable goods, the limitation of the data availability and the repurchase time period constrain the study. In the analysis of the automobile market, those of views might be more persuasive. The purpose of this study is to analyze the structure of automobile market based on some idea suggested by prior studies. Usually the buyers of the automobile tend to buy upper tier when they buy in the next time. That kind of behavior make it impossible to analyze the structure of automobile market under the level of automobile model. For that reason I tried to analyze the market structure in the brand or company level. In this study, consideration data was used for market structure analysis. The reasons why we used the consideration data are summarized as following. Firstly, as the repurchase time cycle is too long, brand switching data which is used for the market analysis of nondurable good is not avaliable. Secondly, as we mentioned, the buyers of the automobile tend to buy upper tier when they buy in the next time. We used survey data collected in the U.S.A. market in the year of 2005 through questionaire. The sample size was 8,291. The number of brand analyzed in this study was 9 among 37 which was being sold in U.S.A. market. Their market share was around 50%. The brands considered were BMW, Chevrolet, Chrysler, Dodge, Ford, Honda, Mercedes, and Toyota. �� ratio was derived from frequency of the consideration set. Actually the frequency is different from the brand switch concept. In this study to compute the �� ratio, the frequency of the consideration set was used like a frequency of brand switch for convenience. The study can be divided into 2 steps. The first step is to build hypothetical market structures. The second step is to choose the best structure based on the hypothetical market structures, Usually logit analysis is used for the choice best structure. In this study we built 3 hypothetical market structure. They are type-cost, cost-type, and unstructured. We classified the automobile into 5 types, sedan, SUV(Sport Utility Vehicle), Pickup, Mini Van, and Full-size Van. As for purchasing cost, we classified it 2 groups based on the median value. The median value was $28,800. To decide best structure among them, maximum likelihood test was used. Resulting from market structure analysis, we find that the automobile market of USA is hierarchically structured in the form of 'automobile type - purchasing cost'. That is, result showed that automobile buyers considered function or usage first and purchasing cost next. This study has some limitations in the analysis level and variable selection. First, in this study only type of the automobile and purchasing cost were as attributes considered for purchase. Considering other attributes is very needful. Because of the attributes considered, only 3 hypothetical structure could be analyzed. Second, due to the data, brand level analysis was tried. But model level analysis would be better because automobile buyers consider model not brand. To conduct model level study more cases should be obtained. That is for acquiring the better practical meaning, brand level analysis should be conducted when we consider the actual competition which occurred in the real market. Third, the variable selection for building nested logit model was very limited to some avaliable data. In spite of those limitations, the importance of this study lies in the trial of market structure analysis of durable good.

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The Current Status of the Discussions on International Norms Related to Space Activities in the UN COPUOS Legal Subcommittee (우주활동 국제규범에 관한 유엔 우주평화적이용위원회 법률소위원회의 최근 논의 현황)

  • Jung, Yung-Jin
    • The Korean Journal of Air & Space Law and Policy
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    • v.29 no.1
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    • pp.127-160
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    • 2014
  • The UN COPUOS was established in 1959 as a permanent committee of the UN General Assembly with the aims to promote international cooperation in peaceful uses of outer space, to formulate space-related programmes within the UN, to encourage research and dissemination of information on space, and to study legal problems arising from the outer space activities. Its members have been enlarged from 24 members in 1959 to 76 in 2014. The Legal Subcommittee, which has been established under COPUOS in 1962 to deal with legal problems associated with space activities, through its first three decades of work has set up a framework of international space law: the five treaties and agreements - namely the Outer Space Treaty, Rescue Agreement, Liability Convention, Registration Convention, Moon Agreement - and the five declarations and legal principles. However, some sceptical views on this legal framework has been expressed, concerning the applicability of existing international space law to practical issues and new kinds of emerging space activities. UNISPACE III, which took place in 1999, served as a momentum to revitalize the discussions of the legal issues faced by the international community in outer space activities. The agenda of the Legal Subcommittee is currently structured into three categories: regular items, single issue/items, and items considered under a multi-year workplan. The regular items, which deal with basic legal issues, include definition and delimitation of outer space, status and application of the five UN treaties on outer space, and national legislation relevant to the peaceful exploration and use of outer space. The single issues/items, which are decided upon the preceding year, are discussed only for one year in the plenary unless renewed. They include items related to the use of nuclear power sources in outer space and to the space debris mitigation. The agenda items considered under a multi-year work plan are discussed in working group. Items under this category deal with non-legally binding UN instruments on outer space and international mechanism for cooperation. In recent years, the Subcommittee has made some progress on agenda items related to nuclear power sources, space debris, and international cooperation by means of establishing non-legally binding instruments, or soft law. The Republic of Korea became the member state of COPUOS in 2001, after rotating seats every two years with Cuba and Peru since 1994. Korea's joining of COPUOS seems to be late, in considering that some countries with hardly any space activity, such Chad, Sierra Leone, Kenya, Lebanon, Cameroon, joined COPUOS as early as 1960s and 1970s and contributed to the drafting of the aforementioned treaties, declarations, and legal principles. Given the difficulties to conclude a treaty and un urgency to regulate newly emerging space activities, Legal Subcommittee now focuses its effort on developing soft law such as resolutions and guideline to be adopted by UN General Assembly. In order to have its own practices reflected in the international practices, one of the constituent elements of international customary law, Korea should analyse its technical capability, policy, and law related to outer space activities and participate actively in the formation process of the soft law.

Evaluation of Skin Dose and Image Quality on Cone Beam Computed Tomography (콘빔CT 촬영 시 mAs의 변화에 따른 피부선량과 영상 품질에 관한 평가)

  • Ahn, Jong-Ho;Hong, Chae-Seon;Kim, Jin-Man;Jang, Jun-Young
    • The Journal of Korean Society for Radiation Therapy
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    • v.20 no.1
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    • pp.17-23
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    • 2008
  • Purpose: Cone-beam CT using linear accelerator attached to on-board imager is a image guided therapy equipment. Because it is to check the patient's set-up error, correction, organ and target movement. but imaging dose should be cause of the secondary cancer when taking a image. The aim of this study is investigation of appropriate cone beam CT scan mode to compare and estimate the image quality and skin dose. Materials and Methods: Measurement by Thermoluminescence dosimeter (TLD-100, Harshaw) with using the Rando phantom are placed on each eight sites in seperately H&N, thoracic, abdominal section. each 4 methods of scan modes of are measured the for skin dose in three time. Subsequently, obtained average value. Following image quality QA protocol of equipment manufacturers using the catphan 504 phantom, image quality of each scan mode is compared and analyzed. Results: The results of the measured skin dose are described in here. The skin dose of Head & Neck are measured mode A: 8.96 cGy, mode B: 4.59 cGy, mode C: 3.46 cGy mode D: 1.76 cGy and thoracic mode A: 9.42 cGy, mode B: 4.58 cGy, mode C: 3.65 cGy, mode D: 1.85 cGy, and abdominal mode A: 9.97 cGy, mode B: 5.12 cGy, mode C: 4.03 cGy, mode D: 2.21 cGy. Approximately, dose of mode B are reduced 50%, mode C are reduced 60%, mode D are reduced 80% a point of reference dose of mode A. the results of analyzed HU reproducibility, low contrast resolution, spatial resolution (high contrast resolution), HU uniformity in evaluation item of image quality are within the tolerance value by recommended equipment manufacturer in all scan mode. Conclusion: Maintaining the image quality as well as reducing the image dose are very important in cone beam CT. In the result of this study, we are considered when to take mode A when interested in soft tissue. And we are considered to take mode D when interested in bone scan and we are considered to take mode B, C when standard scan. Increasing secondary cancer risk due to cone beam CT scan should be reduced by low mAs technique.

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Use of Nuclear Power Sources in Outer Space and Space Law (우주에서의 핵연료(NPS)사용과 우주법)

  • Kim, Han-Taek
    • The Korean Journal of Air & Space Law and Policy
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    • v.22 no.1
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    • pp.29-54
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    • 2007
  • Nuclear Power Sources(NPS) have been used since 1961 for the purpose of generating energy for space objects and have since then been recognized as particularly suited essential to some space operations. In January 1978 a malfuctioning Soviet nuclear powered satellite, Cosmos 954, re-entered the earth's atmosphere and disintegrated, scattering radioactive debris over a wide area of the Canadian Northwest Territory. This incident provided some reasons to international legal scholars to make some principles to regulate using NPS in outer space. In 1992 General Assembly adopted "Principles Relevant to the Use of Nuclear Power Sources in Outer Space". These NPS Principles set out certain legal and regulatory requirements on the use of nuclear and radioactive power sources for non-propulsive purposes. Although these principles, called 'soft laws', are not legal norms, they have much enfluences on state practices such as 1983 DBS Principles(Principles Governing the Use by States of Artificial Earth Satellites for International Direct Television Broadcasting), 1986 RS Principles(Principles Relating to Remote Sensing of the Earth from Space) and 1996 Declaration on International Cooperation in the Exploration and Use of Outer Space for the Benefit and in the Interests of all States, Taking into Particular Account the Needs of Developing Countries. As far as 1963 Declaration of Legal Principles Governing the Activities of States in the Exploration and Use of Outer Space is concerned the main points such as free use of outer space, non-appropriation of celestial bodies, application of international law to outer space etc. have become customary international law binding all states. NPS Principles might have similar characters according to states' willingness to respect them.

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Use of Nuclear Power Sources in Outer Space and Space Law (우주에서의 핵연료(NPS)사용과 우주법)

  • Kim, Han-Taek
    • The Korean Journal of Air & Space Law and Policy
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    • no.spc
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    • pp.35-58
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    • 2007
  • Nuclear Power Sources(NPS) have been used since 1961 for the purpose of generating energy for space objects and have since then been recognized as particularly suited essential to some space operations. In January 1978 a malfuctioning Soviet nuclear powered satellite, Cosmos 954, re-entered the earth's atmosphere and disintegrated, scattering radioactive debris over a wide area of the Canadian Northwest Territory. This incident provided some reasons to international legal scholars to make some principles to regulate using NPS in outer space. In 1992 General Assembly adopted "Principles Relevant to the Use of Nuclear Power Sources in Outer Space". These NPS Principles set out certain legal and regulatory requirements on the use of nuclear and radioactive power sources for non-propulsive purposes. Although these principles, called 'soft laws', are not legal norms, they have much enfluences on state practices such as 1983 DBS Principles(Principles Governing the Use by States of Artificial Earth Satellites for International Direct Television Broadcasting), 1986 RS Principles(Principles Relating to Remote Sensing of the Earth from Space) and 1996 Declaration on International Cooperation in the Exploration and Use of Outer Space for the Benefit and in the Interests of all States, Taking into Particular Account the Needs of Developing Countries. As far as 1963 Declaration of Legal Principles Governing the Activities of States in the Exploration and Use of Outer Space is concerned the main points such as free use of outer space, non-appropriation of celestial bodies, application of international law to outer space etc. have become customary international law binding all states. NPS Principles might have similar characters according to states' willingness to respect them.

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Limitations of National Responsibility and its Application on Marine Environmental Pollution beyond Borders -Focused on the Effects of China's Three Gorges Dam on the Marine Environment in the East China Sea- (국경을 넘는 해양환경오염에 대한 국가책임과 적용의 한계 -중국의 산샤댐 건설로 인한 동중국해 해양환경 영향을 중심으로-)

  • Yang, Hee Cheol
    • Ocean and Polar Research
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    • v.37 no.4
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    • pp.341-356
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    • 2015
  • A nation has a sovereign right to develop and use its natural resources according to its policies with regard to development and the relevant environment. A nation also has an obligation not to harm other countries or damage environments of neighboring countries as consequences of such actions of developments or use of natural resources. However, international precedents induce a nation to take additional actions not to cause more damages from the specific acts causing environmental damages beyond national borders, when such acts have economic and social importance. That is to say that there is a tendency to resolve such issues in a way to promote the balance between the mutual interests by allowing such actions to continue. A solution to China's Three Gorges Dam dilemma based on a soft law approach is more credible than relying on a good faith approach of national responsibilities and international legal proceedings since the construction and operation of the dam falls within the category of exercising national sovereign rights. If a large scale construction project such as the Three Gorges Dam or operation of a nuclear power plant causes or may cause environmental damage beyond the border of a nation engaged in such an undertaking, countries affected by this undertaking should jointly monitor the environmental effects in a spirit of cooperation rather than trying to stop the construction and should seek cooperative solutions of mutual understanding to establish measures to prevent further damages. If China's Three Gorges Dam construction and operation cause or contain the possibility of causing serious damages to marine environment, China cannot set aside its national responsibility to meet international obligations if China is aware of or knows about the damage that has occurred or may occur but fail to prevent, minimize, reverse or eliminate additional chances of such damages, or fails to put in place measures in order to prevent the recurrence of such damages. However, Korea must be able to prove a causal relationship between the relevant actions and resulting damages if it is to raise objections to the construction or request certain damage-prevention actions against crucial adverse effects on the marine environment out of respect for China's right to develop resources and acts of use thereof. Therefore, it is essential to cumulate continuous monitoring and evaluations information pertaining to marine environmental changes and impacts or responses of affected waters as well as acquisition of scientific baseline data with observed changes in such baseline. As China has adopted a somewhat nonchalant attitude toward taking adequate actions to protect against marine pollution risks or adverse effects caused by the construction and operation of China's Three Gorges Dam, there is a need to persuade China to adopt a more active stance and become involved in the monitoring and co-investigation of the Yellow Sea in order to protect the marine environment. Moreover, there is a need to build a regular environmental monitoring system that includes the evaluation of environmental effects beyond borders. The Espoo Convention can serve as a mechanism to ease potential conflicts of national interest in the Northeast Asian waters where political and historical sensitivities are acute. Especially, the recent diplomatic policy advanced by Korea and China can be implemented as an important example of gentle cooperation as the policy tool of choice is based on regional cooperation or cooperation between different regions.

Evaluation of Dose and Position Compensation of Parotid Gland Using CT On-rail System in Head-and-Neck Cancer (두경부 암환자 치료 시 CT On-rail System을 이용한 이하선의 위치 보정 및 선량 평가)

  • Jang, Hyeong-Jun;Im, Chung-Geun;Chun, Geum-Sung;Jeong, Il-Seon;Kim, Hoi-Nam
    • The Journal of Korean Society for Radiation Therapy
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    • v.20 no.2
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    • pp.83-89
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    • 2008
  • Purpose: The checking method of target and normal structure are used by MVCBCT, KVCBCT, CT On-rail System, Ultrasound in H&N cancer patient. In case of MVCT, the utilization of bone structure is valuable to check around tissue. But the utilization of soft tissue is not enough. The point of this paper is dose variation in movable parotid and changeable volume of H&N cancer patient of CT On-rail System. Materials and Methods: The object of H&N cancer patient is 5 in this hospital. The selected patient are scanned ARTISTE CT Vision (CT On-ral System) a triweekly. After CT scanning, tranfered coordinates are obtained by movable of parotid gland comparison with planning image. Checking for the changeable volume of parotid gland. A Obtained CT image are tranfered to the RTP System. So dose variation are checked by following changed volume. Results: The changes of target coordinate by the parotid gland movement are X: -0.4~0.4 cm, Y: -0.4~0.3 cm, Z: -0.3~0.3 cm. the volume of GTV is decreased to about 7.11%/week and then both parotid gland volume are shrinked about 4.81%/week (Lt), 2.91%/week (Rt). At the same time, each parotid gland are diminished in radiation dose as 3.66%/week (Lt), 2.01%/week. Conclusion: Images from CT on the rail System which are able to aquire the better quality images of soft tissue in Target area than MVCBCT. After replanning and dose redistribution by required images, It could gain not only the correction of the patient set-tup errors but exact dose distribution. Accordingly, the delivery of compensated dose, It makes that we could do Adaptive Targeting Radiotherapy and need Real Time Adaptive Targeting Radiotherapy by reduce beam delivary time.

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AN INVESTIGATION OF TRAUMATIC DENTAL INJURIES IN CHILDREN (소아의 치아와 지지조직 외상에 관한 분석)

  • Baik, Byeong-Ju;Yang, Yeon-Mi;Yang, Cheol-Hee;Kim, Jae-Gon
    • Journal of the korean academy of Pediatric Dentistry
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    • v.28 no.4
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    • pp.600-612
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    • 2001
  • The purpose of this study is concerned with an investigation of the actual condition of traumatic injuries of teeth and supporting structures in children to set up possible criteria for prevention and treatment of injured teeth. The materials consisted of the clinical records of 431 traumatically injured teeth of 212 children, accumulated during two years from the first of April in 1998 to the end of March in 2000, supplied from the Dept. of Pediatric Dentistry, Chonbuk National University Hospital. The incidence of injuries in boys was extremely high for permanent teeth, twice as high as in girls. Accidents to primary teeth were most common from 1 to 2 years of age and to permanent teeth were most from 8 to 9 years of age. The most common cause of trauma was a fall for both primary and permanent teeth, followed by collision. The anterior teeth in maxilla was most frequently affected by trauma in both the primary and permanent teeth. The most common type of trauma were loosening for the primary teeth, followed by luxation types which included the intrusion, displacement and extrusion and complete avulsion types. For the permanent teeth, the most common type of trauma were tooth fracture. The most common trauma of soft tissue was laceration of upper lip, lower lip and gingiva of maxilla Concerning treatment at the first visit, primary teeth with only loosening and concussion were not usually treated. Permanent teeth were often treated by crown restorations for crown fractures and by endodontic procedures for pulpal exposure. Though we could elucidate actual condition of traumatic injuries of teeth in children, we should make a follow-up survey to ensure the prognosis of injured teeth and establish the most desirable criteria for traumatized teeth in children.

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Surgical Management of Comminuted Midshaft Clavicle Fractures Using Reconstruction Plate and Circumferential Wiring: Does the Circumferential Wiring Interfere with the Bone Union? (쇄골 간부 복합 골절에서 재건 금속판 및 환 강선을 이용한 수술적 치료: 환 강선이 골 유합을 방해하는가?)

  • Kim, Kyung-Tae;Shin, Chung-Shik;Park, Young-Chul;Kim, Dong-hyun;Kim, Min-Woo
    • Journal of the Korean Orthopaedic Association
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    • v.56 no.3
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    • pp.245-252
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    • 2021
  • Purpose: This study examined the radiological and clinical outcomes of internal fixation using a reconstruction plate and 21G circumferential wire in comminuted midshaft clavicular fractures. Materials and Methods: A retrospective cohort study was performed on 51 patients between 2005 and 2019. Thirty-two patients underwent internal fixation with a reconstruction plate and a 21G circumferential wire with minimal soft tissue detachment, and 19 patients underwent surgery without a wire. The patients were assessed with the radiographic parameters, the University of California at Los Angeles (UCLA) score, and the visual analogue scale (VAS) pain score. Based on this, patients who operated without a circumferential wire were set as the control group, and the differences in bone union between the two groups were compared. Results: Thirty-two patients were followed-up for an average of 65 weeks, and 19 patients in the control group were followed-up for an average of 56 weeks. The radiological evaluation confirmed the anatomical reduction and bone union in all 32 patients. No case of nonunion was present. The UCLA score was 32.38 on average and 33.11 in the control group (p=0.395). The VAS score was 1.00 on average and 0.84 in the control group (p=0.668). A significant difference in the bony union time was observed between the group who underwent internal fixation with a reconstruction plate and a 21G circumferential wire with minimal soft tissue detachment, and the control group (p=0.015). On the other hand, there was no statistical significance when other variables were controlled (p=0.107). Conclusion: For displaced midshaft clavicular fractures, internal fixation using a reconstruction plate and 21G circumferential wire maintained accurate anatomical reduction. The satisfactory clinical and radiological results mean that internal fixation using a reconstruction plate and 21G circumferential wire may be a good option for surgical treatment.

Type I Thyroplasty Using Prefabricated Hydroxylapatite Implant(VoCoM$^{\circledR}$) (미리 제작된 Hydroxylapatite 보형물을(VoCoM$^{\circledR}$) 이용한 제 1 형 갑상성형술)

  • 이현종;정한신;백정환;손영익
    • Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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    • v.14 no.2
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    • pp.117-122
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    • 2003
  • Background and Objectives : $VoCoM^{\circledR}$ is a commercialized set composed of prefabricated hydroxylapatite implants and shims of various sizes which are specially designed for the type I thyroplasty. Even though a previously published preliminary report showed that $VoCoM^{\circledR}$ is a convenient and safe product for the type I thyroplasty, further investigations or experiences are yet to be reported. Authors aimed to evaluate the efficacy of $VoCoM^{\circledR}$type I thyroplasty, and its advantage and/or disadvantage. Materials and Method : Twenty three consecutive patients with unilateral vocal cord palsy enrolled for the study, who received type I thyroplasty with $VoCoM^{\circledR}$ between July 2001 and June 2003. Acoustic, aerodynamic and stoboscopic analyses were performed prior to surgery and 1 to 3 months after surgery. Speech language pathologists evaluated their voice quality by GRBAS scale, and patients themselves reported subjective changes of their voice by visual analog scale. Results : The average time for the operation was 80 min, which is about 30 min less than other methods. Preoperative jitter was 3.25$\pm$1.65% and improved to 1.94$\pm$1.79% postoperatively (p<0.05). Preoperative shimmer was 9.72$\pm$6.56% and improved to 5.61 $\pm$3.76% (p<0.05), Maximal phonation time increased from 4.41$\pm$2.99 to 7.98$\pm$4.35 sec (p<0.05) The postoperative stroboscopy revealed an effective medialization in 91.3% of the patients. The subjective phonetic improvements were reported in 21 out of 23 patients. GRBAS scale improved from 2.71$\pm$0.46 to 1.47$\pm$1.12(p<0.05). Additional medialization with $Gore-Tex^{\circledR}$ was easily performed in two revision cases. Previously inserted $VoCoM^{\circledR}$ implant was hard to remove because of the tight integration of soft tissues around the implant. Side effects such as extrusion or foreign body reaction are not observed. $VoCoM^{\circledR}$ was relatively expensive and costed more than 10 times of $Gore-Tex^{\circledR}$. Conclusion : Prefabricated hydroxylapatitie implant($VoCoM^{\circledR}$) provides a convenient, safe and efficient way of vocal fold medialization. However it is relatively expensive and hard to remove.

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