Design of Multi-Process Capability Analysis Chart for Short-Run Production Process

Ping Ping Zhai 창원대학교 2009 국내석사

I wish to thank many people who offered their time, support and friendship to me during my studies at Quality & Reliability Engineering Center in Changwon National University. First of all, I am greatly indebted to my thesis advisor professor Sang Boo Kim for his invaluable advice, warm encouragement and earnest modification. And I sincerely appreciate his patience and understanding during his supervision. Then I owe my gratitude to two teachers. Professor Tae Kwon Song who is a kind professor, thanks for introducing such an excellent professor to me. Professor Choon Shik Lee who is my favorite professor, I really enjoy his class. Quality & Reliability Engineering Center is not only a study place for me but also as my second home in Korea. Each member in my lab like my family member and because them my life become colorful. I would like to thank Sung Youb Choo for his help on my research. Hyeon Gi Park, thanks for looking after me so much on my life. I also wish to thank two good friends. Min Bo Jo, you are a good Korean teacher for me and you are so humorous. Because you, I laugh more and my study life is no longer boring . Myeong Su Kim, thanks for giving me so many beautiful memories and I hope you can realize your dream. Last but not least, I would express my heartfelt thanks to my parents. brother, sister and my boy friend Lin Wang have given me continuous encouragement and supports. Without them I could not have moved forward, dealt with the difficulties and achieved what I have today. Say goodbye to Changwon National University soon, but never forget this memorable place.

A Comparative Study on Civil Service Evaluation System between South Korea and China

PING, LYU 청주대학교 대학원 2020 국내박사

공무원평가제도는 공무원 인사제도의 중요한 부분으로, 채용제도, 상벌제도, 퇴직제도 등 다른 인사제도에 중요한 영향을 미쳐 많은 학자들의 관심을 끌었다. 본 논문은 선배 학자들의 연구에 기초해 많은 논문, 저작물, 최신 중국의 <공무원법>、<공무원 고시 평가 규정(시행)>, 2019년 새로운 발표된 <공무원의 평시 평가방법(시행)>, 그리고 한국 공무원의 제도에 관한 법률(<국가공무원법>, <국가공무원 평가 규정>, <공직자윤리법>, 2018년 발표된 <공무원 행위 규범(개정)>, <5급 이하 공무원 성과평가 메커니즘> 등을 포함)등을 중국과 한국의 문헌자료 및 법률을 통해 연구를 기반으로 했다. 본 논문에서는 비교연구법, 문헌연구법, 사례분석법 등 연구방법을 부로 사용하였으며, 공우뭔 평가제도의 관련 요인에 기초하여 한•중 양국의 공무원 평가제도를 중점 비교분석하였며, 중국 공무원 평가제도에서의 적극적인 방법을 지적하고, 중국 공무원들이 당면한 문제점과 어려움을 분석하여, 중국 공무원들의 평가 개혁에 적합한 시사점과 조언을 제시하였다. 사고의 방향을 구체적으로 연구하면 다음과 같다. 본 연구에서 세 부분으로 나누어지는데, 첫 번째 부분은 제1장의 연구 사유와 현황 및 한•중 양국 공무원 관련된 기본제도를 비교하였다. 두 번째 부분에서는 제3장부터 제6장까지를 포함하여 공무원 평가의 기본 요소로부터 한•중 양국 공무원 평가제도의 세밀한 비교분석을 실시하였다. 세 번째 부분은 제7장부터 마무리까지의 말로, 이부분은 주로 현재의 한•중 양국 공무원 평가제도의 현황과 문제점, 발전 추세를 분석하여 한국의 공무원 평가가 성공적으로 이루어졌다는 계시 하에 중국의 국정을 결합하고, 중국 공무원 평가의 조작가능성을 건의하며, 사상의식의 건설, 제도의 건설에서 구체적인 실천에 이르기까지 중국 공무원 평가제도의 영향을 미치기를 기대한다. The civil service evaluation system is an important part of the civil service personnel system, which has a critical impact on other personnel systems such as the hiring system, reward and punishment system, compensation system, and retirement system. Therefore, it has attracted lots of attentions of many scholars. Based on the researches of senior scholars, the author did a lot of study work through reading a large number of papers, literature works, the latest National civil service law, Civil Service Evaluation Regulations (Trial implementation), and the Civil Service evaluation method (trial implementation) that has been promulgated in 2019. Meanwhile, the author also comprehensively studied the Korean civil service system and some legal provisions, including the National Civil Servant Law, National Civil Servant Law, Public Official Ethics Law, Civil Servant Code of Conduct (Revision) 2018, and laws and regulations such as the Civil Service Achievement Evaluation System under Grade 5 and other Korean documents. This article mainly uses comparative research methods, literature analysis methods and case analysis methods. Based on the relevant factors of the civil service evaluation system, it focuses on the comparative analysis of the civil service evaluation systems in China and South Korea, and points out the positive practices in the Korean civil service evaluation system. It analyzes the problems and difficulties faced by the evaluation of civil servants in China, and proposes enlightenment and suggestions suitable for the reform of the evaluation of civil servants in China. The specific research ideas are as follows. This research is divided into three parts. The first part is on the origin of the study and current status; the basic system of civil servants in the two countries is compared. The second part includes chapter three to six, starting from the basic elements of civil service evaluation, comprehensively comparing and analyzing the civil service evaluation systems of the two countries. The third part is from the seventh chapter to the conclusion part. This part mainly analyzes the current study status, problems, and development trends of the civil service evaluation system of the two countries. Under the inspiration of the successful practices of the Korean civil service evaluation, combined with China's national conditions, it proposes some practical suggestions for the evaluation of Chinese civil servants from ideological construction, system construction to specific practice. It is expected to have some impacts on the reform of the Civil Service Evaluation System in China.

New p-conjugated materials based upon N-Heterocyclic carbenes and organoboron compounds

PING, LUCY 이화여자대학교 대학원 2018 국내박사

본 박사학위논문은 NHC와 organoboron 화합물에 기반하여 π-conjugated 물질의 발전에 대한 연구를 다루고 있다. 본 논문은 다음과 같은 4개의 장으로 구성되어있다. 1) NHC 퀴논의 첨가, 치환, 고리 수축반응. 2)π-conjugated 물질을 기반으로 한 NHC-borylene의 합성적 탐험 3)ROS sensing을 위한 fluorogenic NHC-borane 발전을 위한 노력 4) NHC ligand를 특징으로 하는 BODIPY양이온 센서에 대한 합성적 노력. 제 I장에서는 NHC와 퀴논 사이의 교차반응성에 대해서 서술하였다. 유기금속반응과 유기촉매반응 안에서 퀴논과 NHCs의 빈번한 사용에도 불구하고, 이 물질들의 직접적인 반응성은 아직 발표되지 않았다. NHCs의 친핵성과 퀴논의 친전자성을 고려했을 때, 이 물질들의 반응성은 보장된다. 현재 단 하나의 퀴논만이 유기촉매반응에서 불활성 산화제로 사용되고 있고 흔히 사용되는 다른 종류의 퀴논으로는 기대하는 같은 생성물을 얻을 수 없다. 5 개의 일반적으로 사용되는 NHC로 22 개의 보고된 퀴논을 스크리닝 한 후, 이들 시약과 실제로 교차반응성이 있음을 확인하여 4 가지 종류의 NHC를 기초로 한 생성물의 합성 및 분리를 유도하였다. 그 결과 할로겐화 p-퀴논과의 친핵성 부가 생성물, dicyano-p-퀴논과 furanone을 기반으로 한 푸시-풀 발색단, o-chloranil을 갖는 쌍극성 NHC-fulvalene 및 알킬 치환 된 o-퀴논을 갖는 -acyl imidazolium cyclopentenone을 합성하고 분리할 수 있었다. 제 II장에서는 B(Ⅰ) 물질들을 합성하기 위한 노력에 대해서 논의한다. 보고 된지 채 10년도 안 되었고, 루이스 염기에 의해서만 안정화되는 메탈프리 borylene의 분리를 포함한 Boron(I) borylene 화학 분야는 천천히 발전해나가고 있다. 그렇기는 하지만 찾기 힘든 이 보론 물질을 성공적으로 분리해낸 연구그룹은 거의 없었다. 전자가 부족한 Borylenes의 특성 때문에, π-공액 borylenes의 합성과 유기 전자 분야에서의 활용은 구상 중에 있었다. 이번 장은 oxazolin-2-ylidene 카빈에 의해 안정화된 aryl borylenes를 개발하기 위한 합성법에 있어서의 어려움을 강조한다. 원하는 전구물질을 성공적으로 분리시킨 후에, borylenes를 만들기 위한 과정 중에 원하는 중간체들을 합성하는 다양한 루트가 시도되었지만, 이러한 노력들은 아직 결실을 맺지 못했다. 제 III장에서는 형광을 발생하는 특징을 가진 NHC-borane ROS 센서들이 소개된다. Boronate ester에 기반하는 현재의 ROS 센서들이 친핵성의 borono-Dakin 산화 반응에 의존하는 반면에, NHC-borane ROS 센서는 HOCl에 의해 친전자적으로 산화된다는 것이 우리 연구실에 의해서 최근에 보고 되었다. 센서들의 형광으로 이어지는 응집 효과를 극복하기 위한 노력으로, imidazolium을 기반으로 하는 형광소로 구성된 NHC-borane을 만들어내는 것이 논의되었다. 결국, 잠재적으로 불안정한 일시적 NHC와 borane 전구물질에 의한 예기치 못한 부반응이 타겟 센서의 분리를 불가능하게 하였다. 제 IV장에서는 4,4-difluoro-4-bora-3a,4a-diaza-s-indacenes (BODIPY) 과의 염료들이 도입되었고 양이온의 BODIPYs를 향한 노력이 논의되었다. 주어진 중성의 BODIPYs는 응집유도 효과(표백과 강화된 방출 모두)에 의해서 악화될 수 있기 때문에, 광화학적으로 안전하고 예측할 수 있는 염료들을 매우 필요로 한다. 최근에 DMAP은 양이온 종을 만들기 위해서 BODIPY의 boron 센터에 결합하는 것을 보여주었다. 비슷한 맥락에서, NHCs가 boron 센터에서 단일 양이온성과 이중 양이온성 종들을 만들어 내기 위한 중립적 리간드로서의 역할을 할 수 있다는 것이 제안되었다. 따라서 이들은 수성 용매 내에서 응집 형성을 꺼려할 것이다. 그러나 차후 합성을 위한 노력은 NHCs와 BODIPYs 사이에서 예상치 못한 산-염기 반응과 친핵성 부반응을 초래했고, 이는 계속되는 합성적 접근을 실행 불가능하게 했다. This Ph.D. thesis discusses the studies investigated for the development of p-conjugated materials based upon N-heterocyclic carbenes (NHCs) and organoboron compounds. It is divided into four sections: 1) the addition, substitution, and ring contraction reactions of quinones with NHCs; 2) the synthetic explorations toward NHC-borylene-based π-conjugated materials; 3) the efforts to develop fluorogenic NHC-boranes for the sensing of reactive oxygen species (ROS); and finally, 4) the synthetic endeavours toward cationic BODIPY sensors featuring NHC ligands. In Chapter I, the cross-reactivity between NHCs and quinones was explored. Despite the common use of quinones and NHCs in organometallic and organocatalytic reactions, their direct reactivity has yet to be reported. Given the nucleophilicity of NHCs and the electrophilicity of quinones, their reactivity is ensured. Currently, only one quinone has been adopted by the synthetic community as an inert oxidant for use in organocatalytic reactions, with other commonly used quinones unable to give the same expected products. After screening the cross-reactivity of 22 reported quinones with 5 commonly used NHCs, the synthesis and isolation of four classes of NHC-based products were found. These belong to: the nucleophilic addition-elimination products with halogenated p-quinones, furanone-derived push-pull chromophores with dicyano-p-quinones, dipolar NHC- fulvalenes with o-chloranil, and a-acyl imidazolium cyclopentenones with an alkyl-substituted o-quinone. In Chapter II, the synthetic efforts toward B(I) materials are discussed. Boron(I) borylene chemistry is a slowly developing field of research where the isolation of metal-free borylene stabilised by Lewis bases was only reported less than a decade ago. Even so, few research groups have successfully isolated this elusive boron species. Given the electron deficiency of borylenes, the synthesis and use of π-conjugated borylenes for organic electronic applications was envisaged. This chapter highlights the synthetic difficulties in the efforts to develop aryl borylenes stabilised by oxazolin-2-ylidene carbenes. After successfully isolating the desired precursors, various synthetic routes to the desired intermediates en route to borylenes were attempted, however these efforts have yet to bear fruit. In Chapter III, NHC-borane ROS sensors with fluorogenic properties are introduced. While current boronate ester-based ROS sensors rely on nucleophilic borono-Dakin oxidations, an NHC-borane ROS sensor that can be electrophilically oxidised by HOCl was recently reported by our group. In the efforts to overcome the aggregation effects leading to this sensors’ fluorescence, this chapter examines the attempts towards an NHC-borane based off an imidazolium-based fluorophore. Ultimately, unexpected side reactions from the potentially unstable transient NHC and borane precursor precluded the isolation of the target sensor. In Chapter IV, the 4,4-difluoro-4-bora-3a,4a-diaza-s-indacenes (BODIPY) family of dyes were introduced and the efforts toward cationic BODIPYs (C+-BODIPYs) were discussed. Given neutral BODIPYs can suffer from aggregation-induced effects (both quenching and enhanced emission), photochemically stable and predictable dyes are highly desired. Recently DMAP was shown to coordinate at the boron centre of BODIPYs to give a cationic species. In a similar vein, it was proposed NHCs could act as neutral ligands at the boron centre to give monocationic and dicationic C+-BODIPY that would disfavour the formation of aggregates in aqueous media. The subsequent synthetic efforts, however, resulted in the identification of unforeseen acid-base and nucleophilic side reactions between NHCs and BODIPYs that made the pursued synthetic approach unviable.

중국과 대한민국 정부의 SNS 로 국민소통 활용에 관한 연구

PING YU 경희대학교 대학원 2024 국내석사

본 연구는 주로 중국과 한국 정부의 SNS 플랫폼 사용을 연구하고 개선 방안을 제 시하고자 한다. 먼저 SNS 플랫폼의 정의와 정부의 SNS 사용에 대한 이론적 배경을 요약하고 정부의 SNS 플랫폼 사용에 대한 기능과 역할을 요정보공개 측면에서는 SNS의 실시간성 때문에 정부의 SNS 플랫폼 활용이 정부 업무공개의 수준과 효과를 높일 수 있다. 정부 정책 결정의 측면에서 볼 때, 국민들은 SNS 플랫폼에서 정무 정보를 빠르게 얻고, 정부 관료나 기관과 실시간으로 소통할 수 있으며, 국민들의 제안이 관련 부처에 빠르게 전달될 수 있고, 정부 부처의 정책 결정에 영향을 미칠 수 있다. 여론 관리 측면에서 정부는 SNS 플랫폼에서 사회적 이슈에 대한 토론에 적시에 참여하고 긍정적인 메시지를 게시하며 부정적인 목소리에 대응함으로써 국 민 여론이 긍정적이고 합리적인 방향으로 발전하도록 안내할 수 있다. 다음으로 중국과 한국 정부를 통해 SNS 플랫폼 사용 현황을 분석한 결과, 정부 가 SNS 플랫폼을 사용하여 국민과 상호작용하는 과정에서 문제점을 발견했다. 중 국 정부가 현재 가장 많이 사용하는 SNS 플랫폼은 틱톡으로, 쇼트 클립 플랫폼에 완전히 익숙해지고 적응한 후 정부의 쇼트 클립 플랫폼 사용의 의미와 가치를 재검 토하기 시작했다. 유엔 전자정부 발전지수 조사에 따르면 2010 년부터 한국의 전자 정부 발전지수는 유엔 회원국 중 줄곧 1 위이다. 한국 정부는 주로 페이스북을 사용 하여 정보를 게시하고, 국민들의 피드백을 받는 데 사용한다. 정부가 SNS 플랫폼을 일상화하는 동안 공공 서비스 제공에서 SNS 플랫폼의 역할은 아직 완전히 발휘되 지 않았으며, 정부의 SNS 플랫폼 사용은 여전히 불충분한 정부 및 국민 상호 작용, 불충분한 여론 관리 및 정치적 오락화 등의 문제가 있다. SNS 플랫폼을 활용해 정부의 일상 업무를 수행하고, 보다 양질의 정부 서비스를 제공하기 위해 정부는 다각도로 고민해야 한다.

Syntactic dependencies in Chinese and their theoretical implications

Ping Xue University Microfilms Intemational 1991 국내박사

New π-conjugated materials based upon N-heterocyclic carbenes and organoboron compounds

Ping, Lucy 이화여자대학교 2018 국내박사

Analysis of Nutritional Quality and Comparison of Brassica Vegetables

Ping-Juan Wang 충남대학교 대학원 2011 국내박사

Brassica genus is remarkable for containing more important agricultural crops than any other genus. Many of them are vegetables, oil crops and feed crops commonly consumed and used in the world. Chinese cabbage (Brassica campestris ssp. pekinensis) is the major component of Kimchi in Korea, Many factors including soil, weather, fertilization and others can affect the chemical composition of Chinese cabbages. Certain cultivars of Chinese cabbages are often cultivated in greenhouses during cold weather periods. Since the soil in a greenhouse is rarely exposed to rain and is repeatedly supplemented with fertilizers (e.g. ammonium sulfate), it can become acidic by the accumulation of N and S after the repeated cultivation of crops. To prevent soil acidification and to supply Ca, farmers often apply Ca(OH)2 or CaCO3. The repeated cultivation of Chinese cabbages in greenhouses definitely affects the quality and composition of the plant. For the cultivation of vegitables, the proper range of soil pH is 6.0-6.5. If there is a severe accumulation of salts, the soil pH may be over pH 7.0. This is usually due to the close system that cause accumulation of phosphate and nitrate (5- to 10-fold accumulation than normal soil). This increases osmotic pressure and quantity of ammonia, and thus Ca(OH)2 is hardly absorbed by plants. In case of Chinese cabbage, if the soil pH is >7, growth is poor and rotten inside because of lack of Ca. This also accelerated by insolublized Mn or B due to a high pH. The pH of some land may be higher than the optimal one (>pH 6.5), affecting the quality of Chinese cabbages. To date, there have been no reports on the effects of soil pH on the nutritional glucosinolates of Chinese cabbages. In this study, 13 cultivars and another 7 were tested to distinguish the effects of cultivar specificity from those of the soil pH, thus providing information useful to food scientists and plant breeder The quality and safety of rapeseed oil is affected by glucosinolate causing feed avoidance by animal and erucic acid causing deteriorate effect on cardiovascular system. To determine the quality of rapeseed oil produced in Korea, 3 random samples (29 #1, 2, and 3) and 2 controls (a traditional and newly bred [Kangyu] cultivars) from various regions in Korea were analyzed. In conclusion, the rapeseed oils produced in Kora are needed to be tested for glucosinolates and probably erucic acid. Carotenoids and chlorophylls are natural pingments that are responsible for the coloration of cabbage. Carotenoids and chlorophylls accumulation appears to be affected by the genetic, physiological and biochemical attributes in plant, is also influenced by environmental growing conditions such as fertility, temperature and light. There have been reported the pigment content of some vegetbles in summer was higher than those in winter, some lower than in winter. In this study, ten cultivars (6 green and 4 red ) of cabbage (Brassica oleracea var capitata) were grown to distinguish cultivar specificity affected by seasons (spring and fall), postion( inner and outer section) and color (red and green). Content of total pigments was highest in #31 sample grown during spring and in inner section of #28 and outer section of #29 sample grown during fall. The highest content of total pigments was #31 and #29 samples, respectively, in the green cabbage and red cabbage. Brassica species are a rich source of health affecting compounds. For developing new varieties of Brassica juncea vegetable in Korea, we introduced two culitvars of red and green mustard (Brassica juncea. cv. guangtou) and described the morphological trails of mustard. The contents of functional and nutritional components of 2 cultivars of mustard were analyzed to compare the effects of color of red leaf and green leaf. The leaf of red mustard had imporved nutritional values (high in Al, Ca, Fe, Mg, Mn, B, vitamin C, and E), better taste (high in reducing sugars) and anticancer functionality (high in glucosinolates, flavonols and carotenoids). Cai xin (Brassica rapa ssp.parachinensis) is native to China and has a strong adaptability. In it was introduced for the firs time to Korea to increase vegetable varieties When people short on vegetables in early spring and late fall, the spring and fall crop of cai xin use as replenish for sh. In this study, It were cultivated from August to October of 2008 in Yesan. To describe the morphological trails of si jiu cai xin and investigate of nutritional components, minerals, flavonols, carotenoids and chlorophylls content. It would be advisable for vegetable companies or breeding scientists to improve native varieties in Korea. Si jiu caixin grows as well in Korea. However, we suggest that the introduced si jiu cai xin should do multi-point experiments for several sucessive year.

A Study of K-means Distributed Clustering Algorithms in Sensor Network

Chen Ping 선문대학교 대학원 2009 국내석사

Nowadays the existing data processing systems can only support some simple query for sensor network. It is increasingly important to process the vast data streams in sensor network, and achieve effective acknowledges for users. In this thesis, we explore some distributed clustering algorithms for sensor network. The proposed algorithms are based on the basic K-means algorithm, and also combine the advantages of clustering data streams at local sensor nodes, together with clustering sensor nodes into different nodes groups. In order to verify the effectiveness of the proposed algorithms, we compare it with other related clustering algorithms to process the data streams in sensor network. From the evaluation experiments, we can verify that the proposed algorithms are flexible for network upgrade, also highly capable of processing vast data streams with less computation time.

Study of Cell-derived Extracellular Matrix for Angiogenesis and Novel Growth Factor Delivery System

DU PING University of Science and Technology 2015 국내박사

Extracellular matrix (ECM) is a highly organized network of proteins and other macromolecules that plays a critical role in cell adhesion, migration, and differentiation. In this study, we hypothesize that ECM derived from in-vitro-cultured cells possesses unique surface texture, topography, and mechanical property, and consequently carries some distinct cues for vascular morphogenesis of human umbilical vein endothelial cells (ECs). Cell-derived matrix (CDM) was obtained by culturing fibroblasts, preosteoblasts, and chondrocytes, respectively, on coverslips and then by decellularizing them using detergents and enzymes. These matrices were named fibroblast-derived matrix (FDM), preosteoblast-derived matrix (PDM), and chondrocyte-derived matrix (CHDM). Immunofluorescence of each CDM shows that some of the matrix components are fibronectin (FN), type I collagen, and laminin. Atomic force microscopy analysis presented that average fiber diameter ranged from 2 to 7 µm and FDM holds much larger fibers. The matrix elasticity measurements revealed that average Young’s modulus of CHDM (17.7 – 4.2 kPa) was much greater than that of PDM (10.5 – 1.1 kPa) or FDM (5.7 – 0.5 kPa). During 5-day culture, EC morphologies were dramatically changed on PDM and FDM, but those on CHDM and gelatin were rather stable, regardless of time lapse. Cell migration assay discovered quicker repopulation of the scratched areas on PDM and FDM than on gelatin and CHDM. A capillary-like structure (CLS) assembly was also notable only in the PDM and FDM, as compared with CHDM, gelatin, or FN that were very poor in CLS formation. Quantitative analysis of mean CLS branch points and branch lengths demonstrated much better angiogenic activity of ECs on PDM and FDM. Interestingly, CLS formation was closely associated with matrix remodeling by ECs and the matrix clearance on PDM with time was sharply contrasted with that on CHDM that majority of the matrix FN was reserved. It was notable that membrane type 1-matrix metalloprotease was deeply involved in the process of matrix remodeling. This study indicates that specific matrix microenvironments are very critical for vascular morphogenesis of ECs, and thus, provide a nice platform for angiogenesis study as well as vascular tissue engineering. Vascular endothelial growth factor (VEGF) is one of the most important signaling cues during angiogenesis. Since many delivery systems of VEGF have been reported, the presentation of VEGF using a more physiologically relevant extracellular matrix (ECM), however, has yet to be thoroughly examined. In this study, we propose that fibroblast-derived extracellular matrix (FDM) is a novel platform for angiogenic growth factor delivery and that FDM-mediated VEGF delivery can result in an advanced angiogenic response. The FDMs, activated by EDC/NHS chemistry, were loaded with varying amounts of heparin. Different doses of VEGF were subsequently immobilized onto the heparin-grafted FDM (hep-FDM); 19.6±0.6, 39.2±3.2, and 54.8 ±8.9 ng of VEGF were tethered using 100, 300, and 500 ng of initial VEGF, respectively. VEGF-tethered FDM was found chemoattractive and VEGF dose-dependent in triggering human umbilical vein endothelial cells (ECs) migration in vitro. When hep-FDM-bound VEGF (H-F/V) was encapsulated into alginate capsules (A/H-F/V) and subjected to release test for 28 days, it exhibited a significantly reduced burst release at early time point compared to that of A/V. The cell proliferation results indicated a substantially extended temporal effect of A/H-F/V on EC proliferation compared to those treated with soluble VEGF. For a further study, A/H-F/V was transplanted subcutaneously into ICR mice for up to 4 weeks to assess its in vivo effect on angiogenesis; VEGF delivered by hep-FDM was more competitive in promoting blood vessel ingrowth and maturation compared to other groups. Taken together, this study successfully engineered an FDM-mediated VEGF delivery system, documented its capacity to convey VEGF in a sustained manner, and demonstrated the positive effects of angiogenic activity in vivo as well as in vitro.

Technical trends and issues of UAV communication systems in cellular network

Wang, Kun Ping Graduate School of Engineering, Yonsei University 2022 국내석사

The research status and industry trends in the field of UAV communications are first investigated, it is known that relying on the existing 4G network deployed on the terrestrial can meet the performance requirements of current UAV services. However, the current network infrastructure is designed and deployed for terrestrial UEs. As the altitude increases, users of aerial UAVs will still face poor wireless signal coverage, which may lead to problems such as dropped calls or wireless connection failures during service. This has also been verified in actual tests. Relevant studies have shown that compared to terrestrial UEs, aerial UAV users have a larger number of cells receiving signals and stronger signals in neighboring cells. Therefore, UAV users experience stronger downlink interference than terrestrial UEs. This directly causes UAV users to experience lower signal-to-noise ratios and low data transmission rates, which in turn affects the quality of UAV services. Similarly, as the altitude increases, the signal propagation mode between aerial UAV users and terrestrial base stations changes from multi-path propagation to line-of-sight propagation. In theory, the uplink interference generated by aerial UEs is greater than the interference generated by terrestrial UEs. Although there is no quantitative assessment of the impact on terrestrial UEs, as the number of UAVs increases, theoretically the overall average throughput of the cell will decrease. In addition, in order to solve the problem of uplink and downlink interference, 3GPP rel-15 proposes a series of solutions to reduce uplink and downlink interference, such as configuring directional antennas on aerial UAV users, applying beamforming technology, and configuring special power control parameters to aerial UEs, etc. With the commercialization of 5G networks, the service level of UAVs in 5G cellular network systems is in urgent need of verification. Through actual tests, the service levels of 5G terminals at different altitudes in the air are verified. The conclusion is that relying on the large bandwidth of the 5G network, compared with the 4G network UAVs to achieve a higher transmission rate in the 5G environment, relying on the existing 5G network can basically meet the communication performance requirements of the UAV services. Of course, the test also found that even in the 5G network environment, the average signal-to-noise ratio experienced by aerial UEs is at least 10dB lower than that of terrestrial UEs. This difference is specifically manifested in the urban environment. As the altitude increases, frequent handovers cause drastic fluctuations in the rate, and the number of dropped calls and RLFs gradually increases. The infrastructure designed and deployed specifically for terrestrial UEs is unreasonable in network deployment when providing wireless access services for aerial UEs. In the future, with the emergence of new vehicles such as air taxis, the network infrastructure specially deployed for aerial UAVs needs to be designed and studied in advance.