충격 특성을 고려한 Tonpilz 변환기의 최적구조 설계

강국진,노용래,Kang, Kook-Jin,Roh, Yong-Rae 한국전기전자재료학회 2008 전기전자재료학회논문지 Vol.21 No.11

The optimal structure of the Tonpilz transducer was designed. First, the FE model of the transducer was constructed, that included all the details of the transducer which used practical environment. The validity of the FE model was verified through the impedance analysis of the transducer. Second, the resonance frequency, the sound pressure, the bandwidth, and the impulsive shock pressure of the transducer in relation to its structural variables were analyzed. Third, the design method of $2^n$ experiments was employed to reduce the number of analysis cases, and through statistical multiple regression analysis of the results, the functional forms of the transducer performances that could consider the cross-coupled effects of the structural variables were derived. Based on the all results, the optimal geometry of the Tonpilz transducer that had the highest sound pressure level at the desired working environment was determined through the optimization with the SQP-PD method of a target function composed of the transducer performance. Furthermore, for the convenience of a user, the automatic process program making the optimal structure of the acoustic transducer automatically at a given target and a desired working environment was made. The developed method can reflect all the cross-coupled effects of multiple structural variables, and can be extended to the design of general acoustic transducers.

Class I Flextensional 변환기의 주파수 특성 변화

강국진,백종후,이영진,Kang, Kook-Jin,Paik, Jong-Hoo,Lee, Young-Jin 한국전기전자재료학회 2009 전기전자재료학회논문지 Vol.22 No.2

We constructed a Class I flextensional transducer, and analyzed the variation of the resonance frequency of the transducer in relation to its structural and material variables. We used the FEM for the analysis. Total length of the transducer, thickness and material properties of the shell have large effects on the resonance frequency. While outer radius of the ceramic stack and material properties of the ceramic stack have no effect on the resonance frequency. In addition, the validation of the FE model was verified by manufacturing and comparison of the impedance analysis. Results of the present work can be utilized to design a Class I flextensional transducers of various resonance frequency.

적용환경을 고려한 Flextensional 변환기의 최적구조 설계

강국진,노용래,Kang, Kook-Jin,Roh, Yong-Rae 한국전기전자재료학회 2008 전기전자재료 Vol.21 No.12

The performance of an acoustic transducer is determined by the effects of many design variables, and mostly the influences of these design variables are not linearly independent of each other. To achieve the optimal performance of an acoustic transducer, we must consider the cross-coupled effects of the design variables. In this study, the variation of the performances of underwater acoustic transducer in relation to its structural variables was analyzed. In addition, the new optimal design scheme of an acoustic transducer that could reflect not only individual but also all the cross-coupled effects of multiple structural variables, and could determine the detailed geometry of the transducer with great efficiency and rapidity was developed. The validation of the new optimal design scheme was verified by applying the optimal structure design of a flextensional transducer which are the most common use for high power underwater acoustic transducer. With the finite element analysis(FEA), we analyzed the variation of the resonance frequency, sound pressure, and working depth of a flextensional transducer in relation to its design variables. Through statistical multiple regression analysis of the results, we derived functional forms of the resonance frequency, sound pressure, and working depth in terms of the design variables. By applying the constrained optimization technique, Sequential Quadratic Programming Method of Phenichny and Danilin(SQP-PD), to the derived function, we designed and verified the optimal structure of the Class IV flextensional transducer that could provide the highest sound pressure level and highest working depth at a given operation frequency of 1 kHz.

적용환경을 고려한 Flextensional 변환기의 최적구조 설계

강국진,노용래,Kang, Kook-Jin,Roh, Yong-Rae 한국전기전자재료학회 2008 전기전자재료학회논문지 Vol.21 No.12

The performance of an acoustic transducer is determined by the effects of many design variables, and mostly the influences of these design variables are not linearly independent of each other. To achieve the optimal performance of an acoustic transducer, we must consider the cross-coupled effects of the design variables. In this study, the variation of the performances of underwater acoustic transducer in relation to its structural variables was analyzed. In addition, the new optimal design scheme of an acoustic transducer that could reflect not only individual but also all the cross-coupled effects of multiple structural variables, and could determine the detailed geometry of the transducer with great efficiency and rapidity was developed. The validation of the new optimal design scheme was verified by applying the optimal structure design of a flextensional transducer which are the most common use for high power underwater acoustic transducer. With the finite element analysis(FEA), we analyzed the variation of the resonance frequency, sound pressure, and working depth of a flextensional transducer in relation to its design variables. Through statistical multiple regression analysis of the results, we derived functional forms of the resonance frequency, sound pressure, and working depth in terms of the design variables. By applying the constrained optimization technique, Sequential Quadratic Programming Method of Phenichny and Danilin(SQP-PD), to the derived function, we designed and verified the optimal structure of the Class IV flextensional transducer that could provide the highest sound pressure level and highest working depth at a given operation frequency of 1 kHz.

구강내 장치를 이용한 수면 무호흡 환자의 치료 증례

강국진,오강섭,이시형,Kang, Kook-Jin,Oh, Kang-Seob,Lee, Si-Hyung 대한수면의학회 1998 수면·정신생리 Vol.5 No.2

OSA(Obstructive Sleep Apnea) is a condition with repeated obstruction of the upper airway while sleeping. This obstruction of the upper airway may result if sleep-induced physiologic change in muscle activity is superimposed on various structural defects of the upper airway. Macroglossia, micrognathia, retrognathia, and decreased airway lumen have all been implicated in OSA. There are a variety of surgical and nonsurgical treatment modalities currently available for OSA. Recently the uvulopalatopharyngoplasty has achieved widespread use, but success rates vary and long-term effects are still unknown. Current nonsurgical treatment methods can be cumbersome and uncomfortable with variable responses. For this case. we diagnosed as OSA by using polysomnographic analysis and cephalometric analysis, and delivered intraoral removable appliance which is more conservative, reversible and easy to use for patient. And we got results that Apnea Index(AI) decreased from 14.4 to 3.1, Total Respiratory Disturbance Index(Total RDI) decreased from 18.1 to 7.0 and removal of chronic headache in daytime.

교정용 골면 고정장치용 초내식성 스테인리스강 Miniplate의 특성

강국진(Kook-Jin Kang),손병화(Byeong-Hwa Sohn),김경남(Kyoung-Nam Kim),박용수(Yong-Soo Park),오근택(Keun-Taek Oh) 대한치과재료학회 2004 대한치과재료학회지 Vol.31 No.3

Mycoplasma pneumoniae 폐렴으로 입원한 소아의 Macrolide 내성과 치료 양상

강국진 ( Kook Jin Kang ),고정희 ( Jeong Hee Ko ),최경은 ( Kyong Eun Choi ),최유미 ( Yu Mi Choi ),이원욱 ( Won Wuk Lee ) 중앙대학교 의학연구소 2018 中央醫大誌 Vol.43 No.1

Pediatric Mycoplasma pneumoniae (M. pneumoniae) infection in Korea is becoming difficult to treat due to the recent rise in macrolide resistance. In this study, we investigated the macrolide resistance rate, clinical features, and treatment response of mycoplasma pneumonia patients. The 23S rRNA gene mutations in 247 patients with M. pneumoniae pneumonia were analyzed and grouped into either macrolide-resistant mycoplasma pneumonia (MRMP) and macrolide-susceptible mycoplasma pneumonia (MSMP) patients. Among patients with mycoplasma pneumonia, 85.8% had MRMP and all were mutations of A2063G. All patients received macrolide antibiotics and received steroid therapy in patients with unresponsive to macrolide. Total fever days was significantly longer in MRMP (7.3 days) than in MSMP (5.6 days, p = 0.009), and febrile days after initiation of macrolides was longer in MRMP (2.1 days) than that of MSMP (1.1 days, p = 0.003). In laboratory finding, only lactate dehydrogenase was significantly higher in MRMP (p = 0.026). The steroid treatment rate was significantly higher in MRMP (36.7%) than MSMP (14.2%) (p = 0.011) and the duration of use was significantly longer in MRMP (3 days) than MSMP (1 day, p = 0.039). The results of this study suggest that steroid therapy can help lower the duration of total treatment in children with macrolide-resistant mycoplasma pneumonia. Chung-Ang J Med 2018; 43(1): 7-13

보육지출에서 나타나는 지역 간 불평등성 연구

강국진 ( Kook Jin Kang ),최정우 ( Jung Woo Choi ),배수호 ( Su Ho Bae ) 한국정책학회 2013 韓國政策學會報 Vol.22 No.4

본 연구는 보건사회연구원에서 구축한 복지재정패널 자료를 활용해 지방자치단체 간 보육지출의 불평등성을 분석하고, 나아가 복지지출 세입원의 성질별(보조금, 자체사업비)?주체별(국비, 시도비, 시군구비)에 따른 지방자치단체 간 불평등성을 살펴보고자 한다. 연구의 시간적 범위는 2008년부터 2011년 총 4년이며, 공간적 범위는 기초자치단체 227개를 대상으로 한다. 분석결과에 따르면, 우선 지방자치단체 간의 보육지출은 상당한 수준의 평등성을 확보하고 있는 것으로 나타났다. 또한 중앙정부 또는 광역지방자치단체의 보조금이 지방자치단체의 부족한 재원을 보완해주는 것으로 나타났다. 하지만, 기초자치단체의 고유재원에 따른 보육지출의 불평등성이 상당히 크게 나타났다. 군과 구의 경우, 국비가 지방자치단체의 보육지출 불평등을 개선하고 있으나, 시의 경우에서는 국비가 보육지출의 불평등을 가중시키는 것으로 나타났다. This paper analyzes regional inequalities in the expenditure of child care across local jurisdictions in Korea. To do that, it uses CV (coefficient of variation) and Gini coefficient, covering the four years from 2008 to 2011 in 227 local jurisdictions. According to research findings, there were no regional differences in child care expenditure per child across local jurisdictions. It was mainly due to the grants-in-aid supported by central government and high level of local governments (that is, provincial and metropolitan governments). But the local expenditure for child care from own source was largely different from local jurisdiction to local jurisdiction.

보육정책의 복지혼합적 고찰

김익균(Kim, Ik Gyun),강국진(Kang Kook Jin) 한국보육학회 2010 한국보육학회지 Vol.10 No.2

외국의 보육정책의 패러다임이 복지혼합의 정부-시장의 이원화 체제의 한계를 극복하기 위하여 사회 공동체적 보육의 역할을 인정하고 이를 위하여 민간비영리 부분과 파트너십을 구축하고 있다면, 우리나라의 보육정책은 가족위임형의 보육에서 국가.사회.가족 책임공유형의 보육정책 이 요구되어 지고 있는 실정이다 또한 민간의존형의 보육에서 보육의 공공성을 강화하며 공급자 중심의 보육정책 에서 수요자 및 공급자 만족형의 보육을 추진정책과제로 제시하고 있다. 본 연구에서는 보육서비스의 공급주체에 따른 국가.시장.가족의 복지삼각모형의 분석틀을 통하여 우리나라 보육서비스의 현황을 분석하고 보육정책의 영역으로 보육대상자 사회적 급여, 전달체계와 재정을 분석하였다 이를 통하여 국가 사회공동체적 보육의 필요성을 논의하고자 하였으며, 보육서비스를 위한 국가(정부)가 제공하는 역할과 기업(시장), 가족(부모) 의 역할과 기능을 제시하여 우리나라 보육정책의 발전방향을 모색하고자 한다. 연구의 목적은 첫째, 보육정책은 복지공급주체 간 어떠한 변화가 있었는가를 살펴보고 둘째 보육정책분석을 통한 보육대상자, 사회적 급여, 전달체계, 재정에서 보육정책의 현황은 어떠한 관계를 가지고 있는가를 통하여 국자 시장 가족의 역할부담은 어떠한 관계를 가지고 있는가를 고찰해 본다. The purpose of this study is to suggest a necessity for the day care policy to provide child care services to all the environmental areas such as family, government, and market beyond simple protection and education. A consideration of the role of state, market and family which are regarded as subjects which provide daycare services accord to the Welfare Triangle Model resulted in a conclusion that though the child care budget is rapidly increasing, the role of state is still insufficient by far. Based on this, an analysis of the daycare policy was conducted by dividing it into child care recipient, social benefit, delivery system, and fiance in accordance with Gilbert's four frameworks of analysis, reaching an interpretation as policy. The government will have to construct a child care infrastructure suitable for the social community above any things.

시뮬레이션을 통한 압전형 초음파 스케일러 개발 및 평가

김철민,이영진,백종후,정영훈,강국진,이정배,이승대,Kim, Chul-Min,Lee, Young-Jin,Paik, Jong-Hoo,Jeong, Young-Hun,Kang, Kook-Jin,Lee, Jeong-Bae,Lee, Seung-Dae 한국전기전자재료학회 2009 전기전자재료학회논문지 Vol.22 No.10

A piezoelectric ultrasonic scaler, usually used to remove the tartar out of teeth and to amputate the pubis, is a recently popular instrument for dental treatment due to its several merits such as small size, low-electric power, precision and low-cost. It has typically two parts of a tip and vibration system, which is also composed of head, piezoelectric elements and tail-mass. The scaler concentrates its displacement on tip and has commonly a resonance frequency at 25~30 kHz, and in order to improve the performance of the scaler, it is important to standardize the size of the vibration system without tip for high performance because scaler in quality differs according to several tips. In this study, a Finite Element Analysis (FEA) was utilized to optimize the structure of ultrasonic scaler in the vibration system. Consequently, this study revealed that influence of several tips on property were minimized and scaler showed good property at the resonance frequency of 28 kHz.