• BMB Reports
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• 제54권1호
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• pp.59-69
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• 2021

The ability to read, write, and edit genomic information in living organisms can have a profound impact on research, health, economic, and environmental issues. The CRISPR/Cas system, recently discovered as an adaptive immune system in prokaryotes, has revolutionized the ease and throughput of genome editing in mammalian cells and has proved itself indispensable to the engineering of immune cells and identification of novel immune mechanisms. In this review, we summarize the CRISPR/Cas9 system and the history of its discovery and optimization. We then focus on engineering T cells and other types of immune cells, with emphasis on therapeutic applications. Last, we describe the different modifications of Cas9 and their recent applications in the genome-wide screening of immune cells.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권4호
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• pp.1389-1408
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• 2021

Proof-of-Work (PoW) is the first and still most common consensus protocol in blockchain. But it is costly and energy intensive, aiming at addressing these problems, we propose a consensus algorithm named Proof-of-Work-and-Block-Compression (PoW-BC). PoW-BC is an improvement of PoW to compress blocks and adjust consensus parameters. The algorithm is designed to encourage the reduction of block size, which improves transmission efficiency and reduces disk space for storing blocks. The transaction optimization model and block compression model are proposed to compress block data with a smaller compression ratio and less compression/ decompression duration. Block compression ratio is used to adjust mining difficulty and transaction count of PoW-BC consensus protocol according to the consensus parameters adjustment model. Through experiment and analysis, it shows that PoW-BC improves transaction throughput, and reduces block interval and energy consumption.

• International Journal of Computer Science & Network Security
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• 제22권3호
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• pp.1-8
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• 2022

Supporting real-time flows with delay and throughput constraints is an important challenge for future wireless networks. In this paper, we develop an optimal scheduling scheme to optimally choose the packets to transmit. The optimal transmission strategy is based on an observable Markov decision process. The novelty of the work focuses on a priority-based probabilistic packet scheduling strategy for efficient packet transmission. This helps in providing guaranteed services to real time traffic in Heterogeneous Wireless Networks. The proposed scheduling mechanism is able to optimize the desired performance. The proposed scheduler improves the overall end-to-end delay, decreases the packet loss ratio, and reduces blocking probability even in the case of congested network.

• 한국작물학회지
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• 제50권5호
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• pp.361-367
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• 2005

Single nucleotide polymorphisms (SNPs) are valuable DNA markers due to their abundance and potential for use in automated high-throughput genotyping. Numerous SNP genotyping assays have been developed. In this report, one of effective and high throughput SNP genotyping assays, which was named the template-directed dye-terminator incorporation with fluorescence polarization detection (FP-TDI) was described. Although the most of this assay succeed, the objective of this work was to deter­mine the reasons for the failures, find ways to improve the assay and reduce the running cost. Ninety $F_2$-derived soybean, Glycine max (L.) Merr., RILs from a cross between 'Pureunkong' and 'Jinpumkong 2' were genotyped at four SNPs. FP measurement was done on $Victot^3$ microplate reader (perkinelmer Inc., Boston, MA, USA). Increasing the number of thermal cycles in the single-base extension step increased the separation of the FP values between the products corresponding to different genotypes. But in some assays, excess of heterozygous genotypes was observed with increase of PCR cycles. We discovered that the excess heterozygous was due to misincorporation of one of the dye­terminators during the primer extension reaction. After pyrophosphatase incubation and thermal cycle control, misincoporation can be effectively prevented. Using long amplicons instead of short amplicons for SNP genotyping and decreasing the amount of dye terminator and Acyclopol Taq polymerase to 1/2 or 1/3 decreased the cost of the assay. With these minor adjustments, the FP-TDI assay can be used more accurately and cost-effectively.

• 한국ITS학회 논문지
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• 제12권2호
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• pp.1-11
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• 2013

본 연구에서는 램프미터링과 요금소 본선미터링을 이용한 고속도로 통합교통관리 전략을 제시하였다. 램프와 본선의 통합 미터링을 위해 FREQ에서 램프미터링 진입허용 교통량의 최적화에 사용되는 Demand-Capacity 모형을 수정하여 최적 신호시간 산정모형을 제시하였다. 본 모형은 구간별 통과교통량을 최대화하는데 목표가 있으며, 본선 요금소 및 램프의 미터링 신호시간을 결정할 수 있다. 서울외곽순환선의 김포요금소~시흥요금소 구간을 대상으로 PARAMICS와 API를 이용하여 시뮬레이션 효과분석을 시행하였다. 시뮬레이션 분석결과, 본선미터링을 통해 램프미터링 단독 운영 대비 본선을 소통원활 상태의 속도로 유지할 수 있었으며, 정체구간에서 본선의 통과교통량이 14% 개선된 결과를 나타내었다. 또한 요금소에서의 신호운영으로 400m의 대기행렬이 발생되나, 정체의 분산으로 인해 본선과 램프 모두에서 보다 효율적 교통운영이 가능함을 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제30권11호
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• pp.1785-1791
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• 2020

In a previous study, the sequential optimization and regulation of environmental parameters using the PhotoBiobox were demonstrated with high-throughput screening tests. In this study, we estimated changes in the biovolume-based composition of a polyculture built in vitro and composed of three algal strains: Chlorella sp., Scenedesmus sp., and Parachlorella sp. We performed this work using the PhotoBiobox under different temperatures (10-36℃) and light intensities (50-700 μmol m^-2 s^-1) in air and in 5% CO₂. In 5% CO₂, Chlorella sp. exhibited better adaptation to high temperatures than in air conditions. Pearson's correlation analysis showed that the composition of Parachlorella sp. was highly related to temperature whereas Chlorella sp. and Scenedesmus sp. showed negative correlations in both air and 5% CO₂. Furthermore, light intensity slightly affected the composition of Scenedesmus sp., whereas no significant effect was observed in other species. Based on these results, it is speculated that temperature is an important factor in influencing changes in algal polyculture community structure (PCS). These results further confirm that the PhotoBiobox is a convenient and available tool for performance of lab-scale experiments on PCS changes. The application of the PhotoBiobox in PCS studies will provide new insight into polyculture-based ecology.

• 한국광학회지
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• 제3권2호
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• pp.77-85
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• 1992

Varied-line spacing concave grating을 이용하여 결상면에서 거의 균일한 분해능을 갖는 평면결상 극자외선 분광기를 설계하엿다. 레이저-프라즈마에서 복사되는 발산광의 집속과 분광기의 수차보정을 위해 toroidal mirror를 사용하였고, 비축광선에 의한 수차를 줄이기 위해 toroidal mirror와 회절격자 사이에 10$\mu \textrm m \times2$mm크기의 입사슬릿을 두었다. 평면결상이 가능한 파장영역은 50~300$\AA$이고, 계산된 분해능은 4000이상이다. 회절격자의 효율과 toroidal mirror에서의 반사율을 고려하면 복사 에너지의 집속도는 toroidal mirror를 사용하지 않았을 때보다 3.5배 증가하고, fluorescence는 파장 100.angs.에서 1000배 이상 증가했다.

• 전기전자학회논문지
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• 제21권2호
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• pp.136-141
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• 2017

본 논문에서는 딥러닝을 PC에 적용하기 위한 메모리 최적화에 관한 알고리즘을 제안한다. 제안된 알고리즘은 일반 PC에서 기존의 딥러닝 구조에서 요구되는 연산처리 과정과 데이터 량을 감소시켜 메모리 및 연산처리 시간을 최소화한다. 본 논문에서 제안하는 알고리즘은 분별력이 있는 랜덤 필터를 이용한 컨볼루션 층 구성 과정, PCA를 이용한 데이터 축소 과정, SVM을 사용한 CNN 구조 생성 등의 3과정으로 이루어진다. 분별력이 있는 랜덤 필터를 이용한 컨볼루션 층 구성 과정에서는 학습과정이 필요치 않아서 전체적인 딥러닝의 학습시간을 단축시킨다. PCA를 이용한 데이터 축소 과정에서는 메모리량과 연산처리량을 감소시킨다. SVM을 사용한 CNN 구조 생성에서는 필요로 하는 메모리량과 연산 처리량의 감소 효과를 극대화 시킨다. 제안된 알고리즘의 성능을 평가하기 위하여 예일 대학교의 Extended Yale B 얼굴 데이터베이스를 사용하여 실험한 결과, 본 논문에서 제안하는 알고리즘이 기존의 CNN 알고리즘과 비교하여 비슷한 성능의 인식률을 보이면서 연산 소요시간과 메모리 점유율에 있어 우수함이 확인되었다. 본 논문에서 제안한 알고리즘을 바탕으로 하여 일반 PC에서도 많은 데이터와 연산처리를 가진 딥러닝 알고리즘을 구현할 수 있으리라 기대된다.

• 분석과학
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• 제24권6호
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• pp.510-518
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• 2011

최근 질량분석기와 다차원 크로마토그래피 분석법과 대용량 데이터를 처리하는 생물정보학 프로그램 등과 같은 복합적인 기술요소들의 발전은 대량 프로테옴을 분석하는 것을 가능하게 했다. 하지만, 이런 대량의 프로테옴을 분석하는 것은 단백질 절편화 과정의 긴 소요 시간과 낮은 재현성으로 인하여 한계를 가진다. 이 연구에서는 어쿠스틱 기술을 이용해 빠르게 단백질을 분해하는 새로운 방법을 제시했다. 이 어쿠스틱 기술의 시간과 강도를 최적화하기 위해서 여러 가지 조건에서 BSA 단백질을 트립신으로 절편화한 후 액체 크로마토그래피와 질량분석기로 분석하였다. 16시간동안 인큐베이션하는 기존의 방법과 슈퍼 어쿠스틱 기술을 사용한 방법을 비교하였을 때 슈퍼 어쿠스틱 기술이 기존의 방법보다 더 높은 아미노산 동정율을 보였으며, 유방암 세포와 같은 단백질 복합체에 적용하였을 때 30분의 절편화 시간에서도 효율적인 결과를 확인할 수 있었다. 이 새로운 방법은 샘플 전처리 과정에서 많은 양의 단백질일지라도 더 좋은 효율성을 가지게 되고 또한, 소비되는 시간도 줄여주며 일정 시간내의 샘플 처리량도 증가하게 된다.

• International Journal of Oral Biology
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• 제37권2호
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• pp.43-50
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• 2012

The use of high throughput screening (HTS) in drug development is principally for the selection new drug candidates or screening of chemical toxicants. This system minimizes the experimental environment and allows for the screening of candidates at the same time. Umbilical cord-derived stem cells have some of the characteristics of fetal stem cell and have several advantages such as the ease with which they can be obtained and lack of ethical issues. To establish a HTS system, optimized conditions that mimic typical cell culture conditions in a minimal space such as 96 well plates are needed for stem cell growth. We have thus established a novel HTS system using human umbilical cord derived-mesenchymal stem cells (hUC-MSCs). To determine the optimal cell number, hUC-MSCs were serially diluted and seeded at 750, 500, 200 and 100 cells per well on 96 well plates. The maintenance efficiencies of these dilutions were compared for 3, 7, 9, and 14 days. The fetal bovine serum (FBS) concentration (20, 10, 5 and 1%) and the cell numbers (750, 500 and 200 cells/well) were compared for 3, 5 and 7 days. In addition, we evaluated the optimal conditions for cell cycle block. These four independent optimization experiments were conducted using an MTT assay. In the results, the optimal conditions for a HTS system using hUC-MSCs were determined to be 300 cell/well cultured for 8 days with 1 or 5% FBS. In addition, we demonstrated that the optimal conditions for a cell cycle block in this culture system are 48 hours in the absence of FBS. In addition, we selected four types of novel small molecule candidates using our HTS system which demonstrates the feasibility if using hUC-MSCs for this type of screen. Moreover, the four candidate compounds can be tested for stem cell research application.