a Conceptual Design

학위논문(박사)--아주대학교 일반대학원 :의학과,2020. 8INTRODUCTION 1 MATERIALS AND METHODS 9 RESULTS 24 DISCUSSION 36 CONCLUSION 47 REFERENCES 48DoctoralIntroduction: Cochlear implants (CIs) have become the standard treatment for patients who suffer from sensorineural hearing loss due to damage or loss of hair cells in the cochlea. However, conventional CIs have some challenges, such as problems caused by the use of extracorporeal devices, and have a very high power consumption for frequency analysis measurements. To overcome these challenges, a fully implantable CI (FICI) was developed. Even the newly developed FICI has some limitations, such as too much ambient noise produced from a subcutaneous microphone and a battery that requires frequent recharging. To solve these two problems, artificial basilar membranes (ABMs) made of piezoelectric materials have been studied. This study aimed to verify the conceptual idea of a totally implantable ABM system. Methods: Using the ABM we developed in a previous study, we constructed an electronic module (EM) for the amplification of electrical output from our ABM and investigated the auditory brainstem responses of deafened guinea pigs that were stimulated by the amplified output of electricity generated by the ABM in combination with the EM in response to an actuator. Further, we implemented an optimal method for coupling ABMs to the middle ear ossicle and explored the possibility of a bioelectronic middle ear microphone. Results: The ABM sensitivity as a sensor was 1.82 mV/µm. When calculated by replacing with sound pressure, the ABM sensitivity was 0.120 mV/Pa in this study. In the ABM plus EM in vivo test, the signal, which was generated from the ABM and amplified by the EM, was able to induce auditory brainstem responses (ABRs) in deafened guinea pigs, indicating its capacity to mimic basilar membrane functions. The threshold of ABR was the actuator's stimulus voltage of 6V. As the intensity of the stimulus increased from 6 V to 10 V, the tracing waveform showed a larger amplitude and shorter latency. In the tube-type connector coupled to the umbo, we measured 120 µV of electrical output from the ABM, which was stimulated by sound (110 dB SPL, 750 Hz). Frequency characteristics showed that ABM with the tube-type connector coupled to the umbo is reduced to three channels compared to six channels in the ABM in response to actuator stimulation. The power of the whole ABM system was 100 times lesser than that of conventional CIs. In the case of the ABM system with umbo connection, the electrical output was 10 times lesser than that of the ABM system without coupling. Conclusion: We developed a prototype of the totally implantable ABM system, consisting of the ABM, EM, and electrode, and assessed its feasibility. We obtained meaningful auditory brainstem responses by implanting it into guinea pigs. The power of the entire ABM system was 100 times lesser than that of conventional CIs. In the case of the ABM system with umbo connection, the electrical output was 10 times lesser than that of the ABM system without coupling. Although at the time there was insufficient electrical power to operate the entire system, we found a possibility of a self-powered ABM system, which might be one of the future options for a completely implantable device. Improving the efficiency of the ABM and developing an efficient ossicular connection (coupling) technology are challenges that need to be studied further

분원성 오염원과 하천수에 대한 Bacteroidales 16S rRNA 분자지표의 식별, 정량 및 계통분류학적 연구

Thesis(doctors) --서울대학교 대학원 :협동과정 농업생물공학전공,2010.2.Docto

Policy System Complexity and Self-organization, and Radical Change of Public Acceptance: A Case Study of the Policy of Locating Radioactive Waste Disposal Facilities in Korea

이 연구는 최근 복잡성, 무질서, 비평형성, 비선형성 등이 강조됨에 따라 새로운 패러다임으로 제시되고 있는 복잡계 이론을 방폐장 입지정책에 적용하여 기존의 연구에서 미흡하였던 부분들에 대한 보완적 설명을 시도하였다. 연구 결과 다음과 같은 사항들을 발견하였다. 첫째, 방폐장 입지 선정정책이 오랜 기간 동안 실패를 거듭하였던 이유로는 다양한 요인들을 지적할 수 있으나, 이 연구에서는 이러한 실패요인들에 대한 긍정적 학습과 오차수정이 원활하게 이루어지지 못했던 방폐장 정책체제의 경직된 자기조직화 과정을 지적하였다. 둘째, 방폐장 입지선정정책이 2005년에 성공을 거둘 수 있었던 요인으로는 비록 단기적으로 방폐장 정책체제가 경직된 자기조직화 과정을 거치면서 입지선정에 실패하였으나 장기적으로 시행착오를 통한 긍정적 학습과 오차수정을 통해 점진적으로 성공의 가능성이 높아지는 자기조직화 과정이 진행되고 있었음을 제시하였다. 셋째, 방폐장 입지정책에 대한 주민들의 수용성이 급격하게 변화한 이유는 방폐장 정책체제가 끊임없는 자기조직화를 통해 성공가능성을 지속적으로 축적해왔다는 점과 함께 새로운 인물들이 방폐장 정책체제의 실질적인 작동을 주도함으로써 새로운 아이디어를 만들어낼 수 있었고 이것이 우호적인 정책환경과 결합되면서 급격한 변화를 유도한 것으로 파악하였다. 특히 경쟁구도를 형성하면서 찬반논쟁이 공개적으로 이루어질 수 있었고, 반핵 시민사회단체의 활동이 둔화되었던 것은 주민들의 방폐장에 대한 수용성을 급격하게 변화시킨 요인이었다. This research analyzed the complexity of policy systems, change of policy, and radical change of policy acceptance through a case study of the policy of locating radioactive waste disposal facilities in Korea. In particular, this study analyzed the case using complexity theory to overcome the limitations of previous studies. According to this analysis, this study determined some implications. First, repeated policy failure originated from inappropriate self-organization in the process of correcting errors. Second, although the cause of failure was related with inappropriate error correction from a short-term perspective, a long-term self-organizing process made the policy succeed in 2005. This means that gradual error correction strengthens the self- organizing process and the possibility of policy success. Third, a radical change of policy acceptance and policy success was made through the interaction of new ideas and a favorable policy environment. The formation of the competitive structure had the pros and cons of the policy debated openly. This affected the positive attitude of the public towards radioactive waste disposal facilities by blocking participation of anti-nuclear groups