Practical applications of solid-state NMR in industry

Taejoon Park 한국분석과학회 2021 학술대회논문집 Vol.2021 No.5

Examining the Validity of an Essay Writing Test Using Rasch Analysis

( Taejoon Park ) 한국중등영어교육학회 2012 중등영어교육 Vol.5 No.2

Since an essay writing test involves various factors affecting students`` scores on the test, those in charge of ensuring the validity of such an assessment program need to gather information that will help them determine whether all aspects of the program are working as intended. In the present study, to examine the validity of the assigned scores for students`` essays, four facets of an essay writing test (i.e., examinee, rater, scoring domain, and rating scale) were examined using item response theory (IRT). The investigation of the examinee facet showed that the writing test used in this study separated students into distinct levels of proficiency. The examination of the rater facet revealed that while the raters differed in severity with which they scored students`` essays, all of them used the scoring rubric in a consistent manner. The analysis of the domain (i.e., overall task fulfillment, content, organization, and language) facet showed that ratings on one domain corresponded well to ratings on the other domains, indicating that a single pattern of writing proficiency emerged across all domains. Finally, the examination of the rating scale facet revealed that the 4-point analytic rating scales ranging from 1 to 4 were appropriately ordered and clearly distinguishable.

A study on BEMS-linked Indoor Air Quality Monitoring Server using Industrial IoT

Taejoon Park,Jaesang Cha 한국인터넷방송통신학회 2018 International Journal of Internet, Broadcasting an Vol.10 No.4

In this paper, we propose an interworking architecture for building indoor air quality monitoring server (BEMS) using IIoT (Industrial Internet of Things). The proposed monitoring server adopts IIoT-based standard protocol so that interaction with BEMS installed in existing buildings can be performed easily. It can effectively communicate with indoor air quality measurement sensor installed in the building based on IIoT, Indoor air quality monitoring is possible. We implemented a proposed monitoring server, and confirmed the availability and monitoring of data from sensors in the building.

Capacity Analysis and Feedback Threshold Optimization in Fair Multiuser Diversity System

Taejoon Kim,Jong-Tae Lim IEEE 2012 IEEE Transactions on Vehicular Technology VT Vol.61 No.9

<P>The scheduling scheme of exploiting multiuser diversity gain increases network capacity drastically; however, feedback information overhead linearly increases as the number of users increases. Thus, the allocation of an optimum amount of system resources in feedback signaling is quite an important problem. We analyze the exact capacity of the contention-based multiuser diversity scheduler, which considers the quantitative feedback overhead. The optimum feedback threshold is derived based on the analyzed capacity model. Moreover, the method of searching the optimum resource to be allocated in feedback signaling is proposed.</P>

Enhancement of the light extraction of GaN-based green light emitting diodes via nanohybrid structures

Taejoon Son,정경영,박진섭 한국물리학회 2013 Current Applied Physics Vol.13 No.6

Improvement in the light extraction efficiency (LEE) of GaN-based green light emitting diodes (LEDs)with ZnO nanostructures synthesized by a hydrothermal method is reported. Formation of ZnO nanorods,hemispheres, and cones was controlled by varying the pH of the aqueous synthesis solution. The shape of the ZnO nanostructures integrated onto the LEDs shows a strong relationship with the LEE characteristics of GaN-based green LEDs. The electroluminescence (EL) intensity of LEDs covered by ZnO nanostructures increased compared to conventional LEDs. In terms of LEE, LEDs with surface-textured ZnO hemispheres showed the highest EL intensity, which can be attributed to an increase in the effective critical angle, the escape cone, and multiple scattering. Finite difference time domain (FDTD)simulation was conducted to theoretically confirm the experimental results.

Examining the sructure of a writing assessment using confirmatory factor analysis

( Taejoon Park ) 한국중등영어교육학회 2015 중등영어교육 Vol.8 No.2

The purpose of this study was twofold: (a) to examine the factorial structure of a writing assessment administered to a group of English learners, and (b) to examine the extent to which the test takers`` performance on the writing assessment is affected by the underlying traits (i.e., the aspects of writing ability being tabbed into by the analytic rating scales) and the test methods (e.g., writing tasks and raters) being used to elicit and score test performance. A series of confirmatory factor analysis (CFA) models were tested for the purpose of seeking the best representation of the underlying trait and method factor structure for the measurement design of the writing assessment. The examination of the factor loadings of the final CFA model revealed that the method factor loadings associated with writing tasks were higher than the trait factor loadings for all but one of the observed variables, indicating the impact of strong task effects on the test takers`` performance on the writing assessment. The implications of the results are discussed in terms of the role of tasks in writing performance assessments.

Precision Targeting Tumor Cells Using Cancer-specific InDel Mutations with CRISPR-Cas9

Taejoon Kwon,Jae Sun Ra,Soyoung Lee,In-Joon Baek,Keon Woo Khim,Eun A Lee,Eun Kyung Song,Daniyar Otarbayev,Woojae Jung,Yong Hwan Park,Minwoo Wie,Juyoung Bae,Himchan Cheng,Jun Hong Park,Namwoo Kim,Yuri 한국고분자학회 2024 한국고분자학회 학술대회 연구논문 초록집 Vol.49 No.1

Queuing Analysis in a Multiuser Diversity System With Adaptive Modulation and Coding Scheme

Taejoon Kim,Jong-Tae Lim IEEE 2011 IEEE Transactions on Vehicular Technology VT Vol.60 No.1

<P>In wireless packet networks, the performance of multiuser diversity schedulers has been analyzed with the saturation assumption; however, the finite queue length effect should be taken into account. We propose a new scheduling scheme exploiting multiuser diversity that considers not only channel information but queue information as well. Considering the finite queue length effect and adaptive modulation and coding scheme (AMCS), we analyze the performance of the proposed scheduler.</P>

Optimal Resource Planning with Interference Coordination for Relay-Based Cellular Networks

( Taejoon Kim ),( Kwanghoon An ),( Heejung Yu ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.11

Multihop relay-based cellular networks are attracting much interest because of their throughput enhancement, coverage extension, and low infrastructure cost. In these networks, relay stations (RSs) between a base station (BS) and mobile stations (MSs) drastically increase the overall spectral efficiency, with improved channel quality for MSs located at the cell edge or in shadow areas, and enhanced throughput of MSs in hot spots. These relay-based networks require an advanced radio resource management scheme because the optimal amount of radio resource for a BS-to-RS link should be allocated according to the MS channel quality and distribution, considering the interference among RSs and neighbor BSs. In this paper, we propose optimal resource planning algorithms that maximize the overall utility of relay-based networks under a proportional fair scheduling policy. In the first phase, we determine an optimal scheduling policy for distributing BS-to-RS link resources to RSs. In the second phase, we determine the optimal amount of the BS-to-RS link resources using the results of the first phase. The proposed algorithms efficiently calculate the optimal amount of resource without exhaustive searches, and their accuracy is verified by comparison with simulation results, in which the algorithms show a perfect match with simulations.

The flexible routing with flex for the fast delivery

TaeJoon Park(박태준),Yerim Chung(정예림) 한국컴퓨터정보학회 2021 韓國컴퓨터情報學會論文誌 Vol.26 No.9

본 논문의 목적은 빠른 배송을 위한 배송 차량의 유연 회차와 크라우드쉬핑(Crowd Shipping) 배달원인 플렉스를 활용한 “유연 회차와 플렉스” 방식을 제안하고, 풀이 알고리즘을 제안하는 것이다. 알고리즘은 선행 연구에서 성능이 검증된 2-opt를 사용하여 차량 경로를 계산하고, 절약 휴리스틱(Saving heuristic)을 변형한 방식으로 플렉스에 할당할 고객을 계산한다. 알고리즘은 차량과 플렉스를 분리하는 것이 아니라, 상호 보완적으로 운용될 수 있게 한다. 이를 위해 차량 정보가 플렉스 할당 과정에 고려되도록 하였다. 본 연구의 실험은 다양한 도심지의 상황을 상정한 Random, Mixed, Cluster 인스턴스로 구성되었다. 실험 결과 모든 인스턴스에서는 플렉스의 사용이 차량 유연 회차의 효율성을 높여주는 것을 확인하였다. 또 플렉스와 배송 지연 시간 비용에 대한 민감도분석에서는 “유연 회차와 플렉스”가 차량만을 사용하는 방식의 차량 대수에 따라 값에 차이를 보였지만, 플렉스 비용이나 배송 지연 시간 비용이 200% 증가하는 경우에도 우위를 유지하는 것을 확인하였다. 본 연구의 결과는 플렉스가 차량과 연계되어 활용되는 경우, 플렉스에 의해 서비스되는 고객뿐만 아니라 차량으로 서비스되는 고객들의 서비스 품질을 높일 수 있음을 보여준다. In this paper, we propose “flexible routing with flex” to provide fast delivery by using the flexible routing for the delivery vehicle and crowd-shipper named flex. To this end, we have introduced an algorithm that can build the delivery plan for delivery vehicles and flexes. The introduced algorithm uses the 2-opt algorithm to construct routes with low complexity and acceptable quality, and the revised saving algorithm to assign customer orders to the flex. The algorithm allows the vehicle and the flex to function complement each other without separating the delivery vehicle from the flex. The experiments consider the 3 different instances named Random, Mixed, Cluster, and show that “the flexible routing with flex” has a better result than “vehicle only”. The sensitivity analysis of the flex cost and time penalty shows “the flexible routing with flex” can provide better service not only to the customers who are serviced by flex but also to the customers who are serviced by the delivery vehicle.