• International Journal of Computer Science & Network Security
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• 제22권6호
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• pp.212-222
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• 2022

There has been a rapid increase in the use of cloud email services. As a result, email encryption has become more commonplace as concerns about cloud privacy and security grow. Nevertheless, this increase in usage is creating the challenge of how to effectively be searching and filtering the encrypted emails. They are popular technologies of solving the issue of the encrypted emails searching through searchable public key encryption. However, the problem of encrypted email filtering remains to be solved. As a new approach to finding and filtering encrypted emails in the cloud, we propose a ciphertext-based encrypted policy attribute-based encryption scheme and keyword search procedure based on hidden policy ciphertext. This feature allows the user of searching using some encrypted emails keywords in the cloud as well as allowing the emails filter-based server toward filter the content of the encrypted emails, similar to the traditional email keyword filtering service. By utilizing composite order bilinear groups, a hidden policy system has been successfully demonstrated to be secure by our dual system encryption process. Proposed system can be used with other scenarios such as searching and filtering files as an applicable method.

• 대한치과기공학회지
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• 제45권1호
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• pp.21-29
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• 2023

Purpose: This study attempted to collect basic data to improve the basic repair ability of university freshmen in a world where the usage of advanced medical devices related to computer programs is now common. Methods: The collected data from 280 university freshmen enrolled in nursing, dental, and health degrees or computer and engineering degrees at K university of Gangwon-do were analyzed using the t-test, ANOVA, correlation analysis, and linear regression analysis using the IBM SPSS Statistics ver. 21.0 (IBM). Results: The mathematical learning status and the detailed factors of basic mathematical ability had a positive (+) correlation. The factors of basic mathematical ability, psychology of learning (p<0.001), method of learning (p<0.001), and propensity to learn (p<0.05) were found to be statistically significant, and the model's explanatory power was 40.0%. Conclusion: As a result of this study and considering that advanced medical devices such as computer-aided design/computer-aided manufacturing and three-dimensional printers are becoming more common and up-to-date in clinical settings, it is determined that nursing and dental health students require education to improve their repair skills.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송∙미디어공학회 2021년도 추계학술대회
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• pp.225-228
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• 2021

최근 모바일 비디오 스트리밍 서비스의 이용자 수가 증가하고 있다. 이에 따라 모바일 환경에 적합한 DASH 비디오 스트리밍 메커니즘이 연구되었고, 이것을 DQN 기법에 의해 개선한 알고리즘은 모바일 네트워크 환경에서 적절한 비디오 품질 선택을 통해 버퍼링을 크게 줄일 수 있었다. 그러나 이는 모바일 요금제로 비디오 스트리밍 서비스를 이용하는 사용자들에게 안정적인 서비스를 제공하기 어렵다. 이에 본 논문은 기존의 DQN 기법에 의한 알고리즘을 발전시켜 사용자의 모바일 요금제에 적합한 비디오 품질을 선택하는 알고리즘을 연구하고 성능 실험 결과를 분석한다. 또한 이 알고리즘을 전체 모바일 비디오 스트리밍 시스템과 통합하여 이용하도록 제안한다.

• 전력전자학회논문지
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• 제18권4호
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• pp.349-358
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• 2013

In this paper, the sensorless MPPT algorithm is proposed where the performance of varied duty ratio change has been improved using multi-layer neuro-fuzzy that aligns with neuro-fuzzy based optimized membership function. Since the change of duty ratio of sensorless MPPT is varied by using the neuro-fuzzy, the MPPT response speed is faster than the convectional method and is able to reduce the steady-state ripple. The neuro fuzzy controller has the response characteristics which is superior to the existing fuzzy controller, because of the usage of the optimal width of the fuzzy membership function. The effectiveness of the proposed method has been verified by simulations and experimental results.

• 제어로봇시스템학회논문지
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• 제9권10호
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• pp.822-831
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• 2003

A computer-vision based pipe-inspection algorithm is developed. The algorithm uses the modified Hough transformation and a line-scanning approach to identify the edge line and the radius of the pipe image, from which the eccentricity and dimension of the pipe-end is calculated. Line and circle detection was performed using Laplace operator with input image, which are acquired from the front and side cameras. In order to minimize the memory usage and the processing time, a clustering method with the modified Hough transformation is introduced for line detection. The dimension of inner and outer radius of pipe is calculated by the proposed line-scanning method. The method scans several lines along the X and Y axes, calculating the eccentricity of inner and outer circle, by which pipes with wrong end-shape can be classified and removed.

• 한국컴퓨터정보학회논문지
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• 제22권2호
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• pp.9-19
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• 2017

Useful continuous sensing applications are increasingly emerging as a new class of mobile applications. Meanwhile, open, multi-use sensor devices are newly adopted beyond smartphones, and provide huge opportunities to expand potential application categories. In this upcoming environment, uncoordinated use of sensor devices would cause severe imbalance in power consumption of devices, and thus result in early shutdown of some sensing applications depending on power-hungry devices. In this paper, we propose EnergyCordy, a novel inter-device energy use coordination system; with a system-wide holistic view, it coordinates the energy use of concurrent sensing applications over multiple sensor devices. As its key approach, we propose a relaxed sensor association; it decouples the energy use of an application from specific sensor devices leveraging multiple context inference alternatives, allowing flexible energy coordination at runtime. We demonstrated the effectiveness of EnergyCordy by developing multiple example applications over custom-designed wearable senor devices. We show that EnergyCordy effectively coordinates the power usage of concurrent sensing applications over multiple devices and prevent undesired early shutdown of applications.

• International Journal of Internet, Broadcasting and Communication
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• 제4권1호
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• pp.13-17
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• 2012

Indexing allows converting raw document collection into easily searchable representation. Web searching by Google or Yahoo provides subsecond response time which is made possible by efficient indexing of web-pages over the entire Web. Indexing process gets challenging when the scale gets bigger. Parallel techniques, such as MapReduce framework can assist in efficient large-scale indexing process. In this paper we propose PDFindexer, system for indexing scientific papers in PDF using MapReduce programming model. Unlike Web search engines, our target domain is scientific papers, which has pre-defined structure, such as title, abstract, sections, references. Our proposed system enables parsing scientific papers in PDF recreating their structure and performing efficient distributed indexing with MapReduce framework in a cluster of nodes. We provide the overview of the system, their components and interactions among them. We discuss some issues related with the design of the system and usage of MapReduce in parsing and indexing of large document collection.

• 한국정보교육학회:학술대회논문집
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• 한국정보교육학회 2005년도 하계학술대회
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• pp.409-415
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• 2005

세계적으로 로봇 산업이 차세대 신성장 동력 산업으로 급부상하여 인간과 상호작용 즉 HRI 연구가 활발히 이루어지고 있는데, 최근 들어 로봇의 교육적 활용 연구가 시작되고 있다. 이에 본 연구에서는 교사 보조 로봇의 수업에서의 활용 가능성을 보기위해 사전에 만화 시나리오를 통한 적합한 교과목 후보를 정하였고, 초등학생 6학년의 기대역할을 갖는 프로토타입 로봇을 설계 개발하여 후보 교과목 수업에 활용하는 실험을 실시하였다. 이를 통해 아동이 로봇에게 기대하는 역할이 실험자의 의도와 일치하는지와 교육적 효과 제고에 기여를 하는지를 알아보고자 하였다. 그 결과, 아동은 교사 보조 로봇을 자신보다 약간 높은 나이로 인식하고, 친근하지만 자신보다 우월하여 자신을 이끌어 줄 수 있는 역할을 기대한다는 것을 알 수 있었다. 또한 교사 보조 로봇 활용이 교사와 아동의 흥미 유발에 있어 매우 효과적임을 보여, 향후 교사 보조 로봇은 ICT 활용 교육의 또 다른 매체로서의 가능성을 확인하였다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.542-542
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• 2002

Geometric correction is a critical step to remove geometric distortions in satellite images. For correct geometric correction, Ground Control Points (GCPs) have to be chosen carefully to guarantee the quality of corrected satellite images. In this paper, we present an automatic approach for geometric correction by constructing GCP Chip database (GCP DB) that is a collection of pieces of images with geometric information. The GCP DB is constructed by exploiting Landsat's nadir-viewing property and the constructed GCP DB is combined with a simple block matching algorithm for efficient GCP matching. This approach reduces time and energy for tedious manual geometric correction and promotes usage of Landsat images.

• Journal of Information Processing Systems
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• 제4권2호
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• pp.41-52
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• 2008

In this paper, we discuss a novel reservation-based, asynchronous MAC protocol called 'Multi-rate Multi-hop MAC Protocol' (MMMP) for multi-hop ad hoc networks that provides QoS guarantees for multimedia traffic. MMMP achieves this by providing service differentiation for multirate real-time traffic (both constant and variable bit rate traffic) and guaranteeing a bounded end-to-end delay for the same while still catering to the throughput requirements of non real time traffic. In addition, it administers bandwidth preservation via a feature called 'Smart Drop' and implements efficient bandwidth usage through a mechanism called 'Release Bandwidth'. Simulation results on the QualNet simulator indicate that MMMP outperforms IEEE 802.11 on all performance metrics and can efficiently handle a large range of traffic intensity. It also outperforms other similar state-of-the-art MAC protocols.