Massive MIMO 시스템을 위한 채널 추정 및 피드백 기법

학위논문 (박사)-- 서울대학교 대학원 : 전기·컴퓨터공학부, 2017. 2. 이정우.To meet the demand of high throughput in next generation wireless systems, various directions for physical layer evolution are being explored. Massive multiple-input multiple-output (MIMO) systems, characterized by a large number of antennas at the transmitter, are expected to become a key enabler for spectral efficiency improvement. In massive MIMO systems, thanks to the orthogonality between different users' channels, high spectral and energy efficiency can be achieved through simple signal processing techniques. However, to get such advantages, accurate channel state information (CSI) needs to be available, and acquiring CSI in massive MIMO systems is challenging due to the increased channel dimension. In frequency division duplexing (FDD) systems, where CSI at the transmitter is achieved through downlink training and uplink feedback, the overhead for the training and feedback increases proportionally to the number of antennas, and the resource for data transmission becomes scarce in massive MIMO systems. In time division duplexing (TDD) systems, where the channel reciprocity holds and the downlink CSI can be obtained through uplink training, pilot contamination due to correlated pilots becomes a performance bottleneck when the number of antennas increases. In this dissertation, I propose efficient CSI acquisition techniques for various massive MIMO systems. First, I develop a downlink training technique for FDD massive MIMO systems, which estimates the downlink channel with small overhead. To this end, compressed sensing tools are utilized, and the training overhead can be highly reduced by exploiting the previous channel information. Next, a limited feedback scheme is developed for FDD massive MIMO systems. The proposed scheme reduces the feedback overhead using a dimension reduction technique that exploits spatial and temporal correlation of the channel. Lastly, I analyze the effect of pilot contamination, which has been regarded as a performance bottleneck in multi-cell massive MIMO systems, and propose two uplink training strategies. An iterative pilot design scheme is developed for small networks, and a scalable training framework is also proposed for networks with many cells.1 Introduction 1 1.1 Massive MIMO 1 1.2 CSI Acquisition in Massive MIMO Systems 3 1.3 Contributions and Organization 6 1.4 Notations 7 2 Compressed Sensing-Aided Downlink Training 9 2.1 Introduction 10 2.2 System Model 13 2.2.1 Channel Model 13 2.2.2 Downlink Channel Estimation 16 2.3 CS-Aided Channel Training 19 2.3.1 Training Sequence Design 20 2.3.2 Channel Estimation 21 2.3.3 Estimation Error 23 2.4 Discussions 26 2.4.1 Design of Measurement Matrix 26 2.4.2 Extension to MIMO Systems 27 2.4.3 Comparison to CS with Partial Support Information 28 2.5 Simulation Results 29 2.6 Conclusion 37 3 Projection-Based Differential Feedback 39 3.1 Introduction 40 3.2 System Model 44 3.2.1 Multi-User Beamforming with Limited Feedback 45 3.2.2 Massive MIMO Channel 47 3.3 Projection-Based Differential Feedback 48 3.3.1 Projection-Based Differential Feedback Framework 48 3.3.2 Projection for PBDF Framework 51 3.3.3 Efficient Algorithm 57 3.4 Discussions 58 3.4.1 Projection with Imperfect CSIR 58 3.4.2 Acquisition of Channel Statistics 61 3.5 Simulation Results 62 3.6 Conclusion 69 4 Mitigating Pilot Contamination via Pilot Design 71 4.1 Introduction 72 4.2 System Model 73 4.2.1 Multi-cell Massive MIMO Systems 74 4.2.2 Uplink Channel Training 75 4.2.3 Data Transmission 77 4.3 Iterative Pilot Design Algorithm 78 4.3.1 Algorithm 79 4.3.2 Proof of Convergence 81 4.4 Generalized Pilot Reuse 81 4.4.1 Concept of Pilot Reuse Schemes 81 4.4.2 Pilot Design based on Grassmannian Subspace Packing 82 4.5 Simulation Results 85 4.5.1 Iterative Pilot Design 85 4.5.2 Generalized Pilot Reuse 87 4.6 Conclusion 89 5 Conclusion 91 5.1 Summary 91 5.2 Future Directions 93 Bibliography 96 Abstract (In Korean) 109Docto

Ein Vergleich der Dichtung von Gottfried Benn und Hyeongdo Gi

학위논문(석사) --서울대학교 대학원 :외국어교육과(독어전공),2010.2.Maste

멀티스케일의 인공 유전자 발현 시스템 개발을 통한 박테리아에서 대사산물 생산 최적화 연구

학위논문(박사) -- 서울대학교대학원 : 공과대학 협동과정 바이오엔지니어링전공, 2024. 2. 서상우.미생물은 유전자 편집이 비교적 간편하고, 다양한 탄소원을 활용하여 고부가 대사산물을 생산할 수 있다는 점에서 다양한 산업에서 활용되어 왔다. 최근에는 지속 가능한 에너지 생산, 폐자원의 재활용, 기후 변화, 환경 오염과 같은 범지구적인 문제를 해결하기 위해 기존의 석유화학 산업에 대한 대안으로써 미생물을 세포공장으로 활용하고자 하는 노력이 진행되고 있다. 미생물 세포공장은 살아있는 생물을 활용해 목적 생화학 물질을 생산한다는 점에서, 균주 생장과 산물 생산의 균형을 고려해야 하며, 세포 내 생분자, 세포, 환경의 상호작용을 적절히 조절해야 한다. 합성 생물학 및 시스템 생물학의 발전으로 인해 복잡하고 역동적으로 유전자 발현을 조절할 수 있는 유전자 부품이 개발되면서, 미생물 세포공장은 점차 실제 산업에도 활용되고 있다. 본 연구에서는 다양한 스케일에서 작동하는 인공 유전자 발현 시스템을 활용해 박테리아에서의 산물 생산을 최적화하였다. 단일 및 다중 유전자 수준에서 작동하는 인공 유전자 부품은 효소 발현과 목적 산물 생산에 직접적으로 영향을 미칠 수 있는 번역 단계를 조절할 수 있었다. 단백질의 발현량과 품질을 향상시키는 것과 더불어, 세포 내 한정된 자원과 에너지를 적절하게 분배하는 문제 또한 산물 대량 생산을 위한 핵심적인 요소이다. 따라서, 합성생물학 도구를 사용해 세포 수준에서 대사 흐름을 최적화함으로써, 박테리아의 복잡한 대사를 효과적으로 조절하였다. 박테리아에서는 유전자로부터 리보솜 결합 부위가 전사되자마자 번역이 개시될 수 있다. 이러한 특징은 박테리아로 하여금 빠른 단백질 생산과 동시에, 손상된 mRNA에서 효소로서의 기능을 상실한 펩타이드도 생산하도록 한다. 제 2장에서는 온전한 단백질의 생산을 높이는 인공적인 단백질 품질 관리 시스템 (ProQC system)을 개발했다. 이 시스템은 진핵생물의 번역 기작을 모방하여 비손상 mRNA에서만 선택적으로 번역이 개시할 수 있었다. 이를 통해 총 생산되는 단백질 중 온전한 단백질의 비율을 획기적으로 향상시켰으며, 결과적으로 고부가 대사산물의 생산성 또한 최대 2.3 배까지 향상시킬 수 있었다. 많은 경우에서 목적 산물의 대량 생산을 위해 숙주에 다중 유전자를 도입하는 과정이 필요하다. 오페론은 제한된 유전자 부품으로 여러 유전자 발현을 제어할 수 있다는 점에서 유망한 전사단위이다. 제 3장에서는 번역 동조 기반의 인공 오페론 번역 시스템을 개발했다. 이 시스템을 활용함으로써 종래의 오페론보다 더 정확하게 유전자 발현을 제어하고, 전사량과 번역량의 변화에도 오페론 구성 유전자 간의 발현 비율을 일정하게 유지할 수 있었다. 이러한 특징은 대사산물 생산 최적화를 위해 다중 유전자의 발현을 효율적이고 예측 가능하도록 만들었다. 고부가 생화학 물질의 생산을 위해 숙주에 도입된 외래 대사 경로는 내재된 대사 경로와 자원 및 에너지 사용을 경쟁하게 된다. 따라서, 대사 흐름을 재구성하여 균주 생장과 산물 생산의 균형을 맞추는 것이 중요하다. 제 4장에서는 목적 산물을 감지할 수 있는 전사 기반의 바이오센서를 사용해 산물 생산과 균주 생장을 연결한 적응 진화를 진행했다. 최종 스크리닝된 진화 균주에 대한 분석 결과, 목적 산물 생산과 균주 생장을 위한 탄소 흐름의 재분배가 발생했음이 규명됐다. 또한 이 균주는 이론적 수율에 가깝게 목적 생산하면서도 활발한 생장을 유지할 수 있었다. 종합하면, 본 연구에서는 다양한 스케일에서 작용할 수 있는 인공적인 유전자 발현 시스템을 통해 유전자 발현과 대사 흐름을 최적화함으로써 박테리아에서의 대사산물 생산을 최적화할 수 있음을 입증하였다. 보고된 시스템은 고부가 대사산물을 생산하는 바이오리파이너리와 더불어 박테리아 기반의 진단 키트, 리빙 테라퓨틱스 등 다양한 분야에도 적용될 수 있을 것으로 전망한다.Microorganisms have been utilized in various industries due to their relative genetic simplicity and ability to produce massive amounts of high-value metabolites. Recently, efforts have been made to harness microorganisms as cell factories in response to global issues such as sustainable energy production, recycling of waste resources, climate change, and environmental pollution. As microbial cell factories rely on living organisms to produce target biochemicals, it is essential to balance cell growth and target metabolite production and control the interactions between intracellular molecules, cells, and the environment. With the advancements in synthetic biology and systems biology, programmable genetic parts have been developed, allowing for the precise and dynamic regulation of gene expression at diverse stages and facilitating the transition of microbial cell factories toward practical industrial applications. In this thesis, synthetic gene expression systems operating at different scales were developed and exploited to optimize metabolite production in bacteria. The synthetic genetic parts working at single-gene and multiple-gene scales could control the translation stage, which is crucial for enzyme expression and directly impacts target metabolite production. Besides improving the protein expression level and quality, the optimal distribution of cellular resources is critical for enhancing metabolite production. Hence, the metabolic flux at the whole-cell scale was optimized by effectively regulating the complex metabolism in bacteria using programmable synthetic biology tools. In bacteria, translation can initiate as soon as the ribosome-binding site is transcribed from the gene. This feature enables rapid protein production in bacteria but can lead to the production of non-functional peptides from truncated mRNA. In Chapter 2, a synthetic protein quality control system (ProQC system) was developed to enhance the production of intact proteins. The system could selectively initiate translation only from undamaged mRNA, mimicking the translation mechanism in eukaryotes. As a result, the ratio of intact proteins among the total produced proteins was significantly improved, leading to an increase of up to 2.3-fold in the productivity of high-value metabolites. Introducing multiple genes into the host is often necessary for the high-yield production of target molecules. Operon is a promising transcription unit that efficiently expresses various genes with limited genetic parts. In Chapter 3, an artificial operon expression system based on a translational coupling mechanism was developed. The system could precisely control the translation of operon, maintaining a specific expression ratio between target genes, regardless of transcriptional or translational change. This feature led to the efficient and predictable expression of multiple genes for optimizing biochemical production. The introduced foreign metabolic pathways compete with the host strain's endogenous metabolic pathways for cytosolic resources. Thus, reconstructing the metabolic flux to balance target production and cell growth is essential for optimal production. In Chapter 4, a transcription-based biosensor detecting the target biochemicals was coupled with adaptive laboratory evolution to rebalance metabolic flux. The analysis of the final evolved strain indicated a redistribution of carbon flow between product formation and strain growth, allowing for the production of target metabolite close to the theoretical yield while maintaining high cell biomass. In conclusion, this thesis demonstrated that the synthetic gene expression systems tailored to different scales and stages can effectively control gene expression and metabolic flux, optimizing metabolite production in bacteria. The systems developed here could be applied to biorefinery for high-value metabolite production and other diverse fields, such as diagnostics and living therapeutics.Abstract i List of Tables vii List of Figures viii Chapter 1. Introduction 1 1.1. Bacteria as microbial cell factories 2 1.1.1. Regulation of transcription stage 3 1.1.2. Regulation of post-transcription and translation stage 4 1.1.3. Regulation of post-translation and metabolite production stage 5 1.2. Advanced synthetic biology tools for optimizing metabolite production in bacteria 7 1.2.1. Ribonucleic acid-based devices 9 1.2.2. Transcription-based biosensor 13 1.3. The scope of the thesis 17 Chapter 2. Synthetic protein quality control to enhance full-length translation in bacteria 20 2.1. Abstract 21 2.2. Introduction 23 2.3. Materials and Methods 26 2.3.1. Bacterial strains, plasmids, primers and reagents 26 2.3.2. Construction of the synthetic expression cassette 37 2.3.3. Kinetic analysis of the ProQC system and the toehold system 38 2.3.4. Validation of the intramolecular interaction between the switch and the trigger sequences 39 2.3.5. Preparation of standard curves plotting fluorescent signal versus each reporter protein concentration 40 2.3.6. In vivo protein-quality analysis 41 2.3.7. Protein quality analysis by western blotting 42 2.3.8. Verification of applicability of the ProQC system on general proteins 44 2.3.9. Droplet digital PCR (ddPCR) analysis 46 2.3.10. Examination of circularization of mRNA on the expression 47 2.3.11. 3-HP production and metabolite quantification 47 2.3.12. Violacein production and metabolite quantification 48 2.3.13. Lycopene production and metabolite quantification 50 2.3.14. Effects of implementing the ProQC system on other enzymes 51 2.4. Results and Discussion 52 2.4.1. Design of the synthetic ProQC system 52 2.4.2. Full-length protein synthesis using the ProQC system 58 2.4.3. Tunable gene expression using the ProQC system 71 2.4.4. Applying the ProQC system for biochemical production 73 2.4.5. Discussion 80 2.5. Conclusion 83 Chapter 3. Translational coupling-based synthetic operon expression system for consistent polycistronic expression ratio in bacteria 84 3.1. Abstract 85 3.2. Introduction 87 3.3. Materials and Methods 90 3.3.1. Bacterial strains, media, and culture conditions 90 3.3.2. Reagents and oligonucleotides 103 3.3.3. Plasmids and mutant strain construction 104 3.3.4. Verification of translational coupling effect by fluorescence assay 107 3.3.5. Droplet digital PCR (ddPCR) analysis 110 3.3.6. 3-HP production and metabolite quantification 110 3.3.7. Lycopene production and quantification 111 3.3.8. PHB production and metabolite quantification 113 3.4. Results and Discussion 114 3.4.1. Design and screening of translational coupling-based expression module 114 3.4.2. Component validation of the TCS 120 3.4.3. Applying the TCS for optimized biochemical production 135 3.4.4. Discussion 139 3.5. Conclusion 142 Chapter 4. Synthetic biosensor accelerates evolution by rewiring carbon metabolism toward specific metabolite 143 4.1. Abstract 144 4.2. Introduction 146 4.3. Materials and Methods 149 4.3.1. Key resources table 149 4.3.2. Data and code availability 152 4.3.3. Bacterial strains and mutant construction 153 4.3.4. Reagents and oligonucleotides 160 4.3.5. Detailed construction of plasmids 161 4.3.6. Medium and culture conditions 163 4.3.7. Adaptive laboratory evolution 164 4.3.8. Metabolite quantification 165 4.3.9. Whole-genome resequencing 166 4.3.10. Cyclic AMP assay 166 4.3.11. Purification of adenylyl cyclase 167 4.3.12. Adenylyl cyclase assay 168 4.3.13. RNA-seq expression profiling 168 4.3.14. Western blot analysis 169 4.3.15. ChIP-exo 170 4.3.16. Nanoluciferase assay 173 4.3.17. GAPDH activity assay 173 4.3.18. Evaluation of predicted 3-HP transporters 174 4.3.19. Analysis of whole-genome resequencing 174 4.3.20. Analysis of the conservation score 175 4.3.21. RNA-seq output processing 175 4.3.22. ChIP-exo output processing 176 4.4. Results and Discussion 177 4.4.1. Implementation of ALE using a biosensor based on the selection method 177 4.4.2. Investigation of the evolved strains 183 4.4.3. Identification of the properties of mutant proteins 190 4.4.4. Evaluation of the effect of gapA and transporter genes 203 4.4.5. Synergistic effect of the mutations 214 4.5. Conclusion 216 Chapter 5. Overall conclusion and further suggestions 217 5.1. Development of multiscale synthetic gene expression systems for optimizing metabolite production in bacteria 218 5.2. Further suggestion 1: Exploitation of novel switch-trigger pair showing various expression levels and orthogonality 221 5.3. Further suggestion 2: Design and development of entirely artificial TCS biopart 222 References 224 List of publications 240 Abstract in Korean 242박

메탄자화균 DH-1의 SoxR 전사 조절 네트워크 규명

학위논문 (석사)-- 서울대학교 대학원 : 공과대학 협동과정 바이오엔지니어링전공, 2018. 8. 서상우.Methanotrophs are bacteria that use methane as a sole carbon source and energy source. Since methane takes up almost 90% of natural gas and shale gas and causes global warming, methanotrophs that consume methane are considered as promising industrial strains. Methylomonas sp. DH-1, a novel methanotroph, has a lot of merits such as fast growth, high methanol resistance, innate carotenoid pathway, and so on. However, lack of physiology and genetics about this strain and absence of proper metabolic engineering tools are the bottleneck in industrial application of Methylomonas sp. DH-1. Thus, it is required to understand its genetic and physiologic characteristics and engineering tools tailored to this strain, so that it can be used in diverse industries. We focused on understanding regulatory networks in Methylomonas sp. DH-1 particularly in response to oxidative stress. SoxR, a known transcriptional regulator that governs transcription against oxidative stress, has different mechanism in enterobacteria and non-enterobacteria. When superoxide, nitric oxide, or redox active compounds exist in enterics, SoxR is activated and genes coding proteins that defend cells against oxidative stress are transcribed. SoxR in non-enterics in known not to regulate superoxide dismutase or else. Understanding SoxR transcriptional regulatory network in methanotroph lets this strain be used in various ways. In this study, genome-wide SoxR transcriptional regulatory network in Methylomonas sp. DH-1 was elucidated. SoxR of Methylomonas sp. DH-1 was firstly selected from four candidate proteins. Recombination and epitope tagging strategy, and sequencing library protocols were constructed specific to Methylomonas sp. DH-1. Based on RNA-seq of wild-type and SoxR knock-out mutant under both methane and methanol conditions, SoxR-dependent genes were selected. The number of differentially expressed genes in each condition was 522 and 260, respectively. Genome-wide binding sites of SoxR were also identified by Chromatin Immunoprecipitation sequencing (ChIP-seq) under both conditions. By combining transcriptome with genome-wide binding sites, YgiT-type zinc finger protein (AYM39_RS22995) was identified as SoxR regulon.Abstract.................................................................................... iv List of Tables...................................................................... viii List of Figures...................................................................... ix Chapter 1. Introduction............................................. 1 1.1 Need for making use of methanotrophs in industry..................... 1 1.2 Methylomonas sp. DH-1 as a promising industrial strain......... 3 1.3 SoxR transcriptional regulator in bacteria........................................ 4 1.4 The scope of this study......................................................................... 6 Chapter 2. Materials and methods.......................... 8 2.1 Bacterial strains, media, and culture conditions............................. 8 2.2 Design and construction of linker-8X myc-KanR cassette......... 8 2.3 Preparation of DNA fragments for recombination to construct SoxR knockout mutant......................................................................... 11 2.4 Preparation of DNA fragments for recombination to construct SoxR-myc mutant.................................................................................. 12 2.5 Electroporation-based recombination of DNA fragments in Methylomonas sp. DH-1.................................................................... 12 2.6 RNA-seq.................................................................................................... 15 2.7 ChIP-seq.................................................................................................... 16 Chapter 3. Results and discussion........................ 18 3.1 Selection of SoxR from candidate genes...................................... 18 3.2 Comparison of transcriptional levels between wildtype and SoxR knockout mutant in methane condition.............................. 18 3.3 Comparison of transcriptional levels between wildtype and SoxR knockout mutant in methanol condition............................. 25 3.4 Epitope tagging strategy on Methylomonas sp. DH-1............ 27 3.5 Genome-scale binding profiles of SoxR........................................ 30 Chapter 4. Conclusion..................................................................................... 37 References............................................................................................................. 39 Supplements......................................................................................................... 44 국문 초록................................................................................................................ 61Maste

Development of the Wheel Loader Front Linkage Retaining High Breakout force and Small Angle Change of an attachment

학위논문 (석사)-- 서울대학교 대학원 : 기계항공공학부, 2012. 8. 김종원.휠로더의 대표적인 프런트 링키지 구조에는 지-바 타입(Z-bar type)과 패럴렐 타입(Parallel type) 두 가지 구조가 있다. 지-바 타입은 굴삭력이 매우 좋으나 작업 구간에서 작업부의 각도 변화가 심하다. 반면 패럴렐 타입의 경우 작업부의 각도 변화가 작지만, 실린더의 수축에 의하여 굴삭 작업이 이루어지기 때문에 매우 비효율적이고 굴삭력이 작다. 따라서 두 가지 타입 휠로더의 장점을 동시에 확보할 수 있는 독창적인 프런트 링키지의 개발이 필요하다. 본 논문에서는 지-바 휠로더의 굴삭력을 유지하면서 작업 전 구간에서 작업부의 각도변화가 작은 새로운 휠로더 프런트 링키지 메커니즘을 고안하였다. 또한 새로운 링키지에 대한 기구학 해석을 통해 작업구간에서 작업부의 각도변화를 도출하고, 정역학 해석을 통해 굴삭력을, 동역학 해석을 통하여 작업 구간에서 실린더에 부가되는 반력을 도출한다. 또한 이를 토대로 설계 변수인 핀 포인트의 위치를 가지치기 방식의 완결탐색방법을 통해 최적화 하여, 지-바 수준의 굴삭력을 유지하면서 작업부의 각도변화를 최소화 하였다. 그 결과 굴삭력은 12.6 ton으로 지-바 타입 수준의 굴삭력(12.7 ton)을 확보하였으며, 작업부의 각도변화는 틸팅(tilting) 시 12.5˚, 노-틸팅(no-tilting) 시 3.4˚로 지-바 타입 대비 각각 38.1 %, 91.3 % 향상되었음을 확인하였다.There are two typical type of wheel loader front linkage, Z-bar type and Parallel type. Z-bar type has a high breakout force, but a big angle change of attachment. On the other hand, parallel type has a small angle change of attachment but a low breakout force. So it is needed to develop new front linkage retaining merit of two type of wheel loader This paper presents to develop the new wheel loader front linkage simultaneously retaining a high breakout force of the Z-bar type level and a small angle change of attachment in a trajectory. Also it is presented to derive a angle change of attachment by kinematic analysis, breakout force by static analysis, and reaction force acted on cylinder by dynamic analysis. In addition, position of pin-point is optimized through branch stretching type exhaustive search method. As a result, breakout force of new front linkage is 12.6 ton that is similar to Z-bar type. Also angle change of an attachment is 12.5˚in tilting trajectory and 3.4˚in no-tilting trajectory초록 1. 서론 1.1 연구배경 및 연구동기 1.2 관련 연구 조사 1.3 연구목표 및 내용 2. 휠로더 신규 프런트 링키지 고안 3. 기구학 해석 4. 역학해석 4.1 정역학 해석을 통한 굴삭력 도출 4.2 동역학 해석을 통한 실린더 반력 도출 5. 이론해석결과의검증 5.1 기구학 해석의 검증 5.2 정역학 해석의 검증 5.2 동역학 해석의 검증 6. 핀 포인트 위치 최적 설계 6.1 핀 포인트 위치 최적화 6.2 최적화 수행 결과 7. 결론 8. 참고문헌 AbstractMaste

Estimating the Impacts of Investment in a National Open Repository on Funded Research Output in South Korea

Open access is a paradigm whereby the electronic versions of scholarly publications are made freely accessible without any restrictions. It is actively promoted globally and is also promoted domestically in accordance with this global trend. However, there is a growing need to evaluate existing activities and to seek policies for the steady spread of open access. This study examines the necessity of switching to a national repository from existing institutional repositories through policy direction analysis of open repositories. We examined domestic open access policies by analysing various overseas cases and the situation in South Korea. Finally, we determined the validity of investment in a national repository by analysing its social and economic impacts using the modified Solow-Swan model. The main parameters for applying the modified Solow-Swan model were estimated, and the domestic research and development expenditure was predicted via a regression method. Then, we applied a range of rate of returns to research and development (10% to 50%) to various scenarios and examined the effects of increasing accessibility and efficiency by 1% to 10%. We found that the implementation of a national open access repository in South Korea would have a substantial impact (to the tune of 147 billion won), without considering the potential costs of such a repository. Based on the estimates of the social and economic impact of a national repository, the implementation of a national open access repository in South Korea is economically viable. Besides having beneficial social and economic impacts, a national repository is expected to enhance awareness of open access among Korean researchers and institutions

A study on the evaluation of convertible bond

학위논문(석사) - 한국과학기술원 : 테크노경영대학원, 1998.2, [ iii, 54 p. ]한국과학기술원 : 테크노경영대학원

Development of an efficient microbial process using non-edible biomass by engineering Vibrio sp. dhg

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Vibrio-based microbial platform for accelerated lignocellulosic biomass refinery

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