• 정보보호학회논문지
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• 제27권3호
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• pp.459-466
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• 2017

가장 널리 사용되는 오픈 소스 프로젝트 중 하나인 OpenSSL은 대부분의 웹 사이트, 서버 및 클라이언트를 보호하는 데 사용되는 암호화 라이브러리이다. OpenLLS을 사용하여 SSL 혹은 이것으로부터 나온 TLS 프로토콜로 안전하게 통신할 수 있다. 시스템의 지속적 보안성 유지를 위해 암호 프로토콜은 업데이트되고 개선되어야 하므로, 이 라이브러리는 새로운 암호화 방법을, 특히 대칭 암호화 프로토콜을, 시스템에 통합하여 구현하는 일이 간단하도록 작성되었다. 그러나 비대칭 암호화 프로토콜을 추가 할 때는 훨씬 더 복잡해진다. 본 논문에서는 OpenSSL 기반 사용자 지정 암호 프로토콜 구현 방안 도출을 위하여 OpenSSL 라이브러리의 세부 아키텍처를 파악하고 설명한다. 그리고 대칭키와 비대칭 암호화 기반 사용자 지정 프로토콜을 수용하기 위해 OpenSSL 라이브러리를 수정하는 방법을 제시한다.

• 대한치과의사협회지
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• 제50권3호
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• pp.118-125
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• 2012

CAD/CAM systems (computer-aided design / computer-aided manufacturing) used for decades in restorative dentistry have its application to implant dentistry. This study aimed to overview CAD/CAM systems used implant dentistry, especially emphasizing custom implant abutments manufacturing. CAD/CAM custom abutments present the advantages of being specific to each patient and providing a better fit than the stock and cast custom abutments. This cutting edge technology of virtual-designed and computer-milled implant abutments will likely replace traditional implant restorative protocols and become the standard for implant dentistry in the foreseeable future.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권6호
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• pp.1113-1132
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• 2011

In wireless sensor networks (WSNs), most energy saving asynchronous MAC protocols are custom tailored for unicast communications only. However, broadcast protocols are very commonly used in WSNs for a variety of functionalities, such as gathering network topology information, event monitoring and query processing. In this paper, we propose a novel low-power asynchronous broadcast MAC protocol called Alarm Broadcast (A-CAST). A-CAST employs the strobe preamble that specifies the residual waiting time for the following data transmission. Each receiver goes back to sleep upon hearing the strobe preamble for the residual time duration, to conserve energy and to wake up just before data transmission starts. We compute the energy consumption of A-CAST via rigorous mathematical analysis. The analytic results show that A-CAST outperforms B-CAST, a simple broadcast extension of the well-known B-MAC. We also implement A-CAST on sensor motes and evaluated its performance through real experiments. Our experimental results show that A-CAST reduces the energy consumption by up to 222% compared to the previously proposed protocols.

• 한국통신학회논문지
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• 제31권3A호
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• pp.360-367
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• 2006

본 논문에서는 RFID 표준 중의 하나인 EPC 글로벌 제너레이션 2 클래스 1(EPC global generation 2 class 1) 태그의 설계에 대하여 논하였다. RFID 표준에 관한 연구나 충돌 방지(anti-collision) 알고리즘에 관한 연구는 많이 진행이 되었지만 태그디지털 코덱 아키텍처 하드웨어의 구체적인 설계에 관한 논문은 아직 없는 실정이기 때문에 본 논문에서 연구하게 되었다. 본 논문의 목적은 RFID 태그 블록의 구성 및 기능설계에 관한 연구를 함으로써 대략적인 전력소모, 하드웨어 크기 등에 대한 방향을 제시하고있다. 스탠더드 셀 라이브러리 합성방식을 사용하여 합성한 결과 설계된 디지털 코덱의 크기는 111640.328125개(인버터 개수)였고 소모 전력은 동적 소모 전력을 기준으로 10.3575uW로 추정되었다. 풀커스텀(full-custom)방식을 사용할 경우, 더욱 개선된 효과를 발휘할 것으로 보인다.

• Journal of Information Science Theory and Practice
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• 제9권4호
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• pp.50-62
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• 2021

This study aims to unravel the shift in the customary method of disseminating information about the ritual of Perang Topat (literally translated as "rice-cake war") as carried out by the custom community of Kemaliq Lingsar in the West Lombok Regency of Indonesia during the COVID-19 pandemic. Grounded in the ethnography of communication research methodology, this study examines the process of the cultural ritual during the 2020 period of the pandemic and compares it to the ones held in 2018 and 2019 (before the current pandemic). Drawing on findings from observations, in-depth interviews, and documentation, it was revealed that the traditional or custom-oriented community of Kemaliq Lingsar abandoned all three prominently used methods of disseminating the information of the Perang Topat ritual that had been used prior to the pandemic, and that they were replaced by a strategy with solely face-to-face (FTF) interpersonal communication carried out by visiting the homes of the target participants of the cultural event. This method was relevant to the current viral crisis because it enabled the committee to minimize the number of spectators which might potentially violate COVID-19 health protocols. This finding also reinforces the hypothetical statement that interpersonal communication via FTF is effective in disseminating information in a limited manner and empowering the emotional bond between the individuals who share relationships and similar interests. The findings of the present study can be a reference for any events where physical distancing must be strictly imposed and require a limit to the number of participants during the pandemic.

• JSTS:Journal of Semiconductor Technology and Science
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• 제17권4호
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• pp.505-513
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• 2017

As mobile systems are performing various functionality in the IoT (Internet of Things) era, network-on-chip (NoC) plays a pivotal role to support communication between the tens and in the future potentially hundreds of interacting modules in system-on-chips (SoCs). Owing to intensive research efforts more than a decade, NoCs are now widely adopted in various SoC designs. Especially, studies on application-specific NoCs (ASNoCs) that consider the heterogeneous nature of modern SoCs contribute a significant share to use of NoCs in actual SoCs, i.e., ASNoC connects non-uniform processing units, memory, and other intellectual properties (IPs) using flexible router positions and communication paths. Although it is not difficult to find the prior works on ASNoC synthesis and optimization, little research has addressed the issues how to convert different protocols and data widths to make a NoC compatible with various IPs. Thus, in this paper, we address important issues on ASNoC implementation to support and convert multiple interfaces. Based on the in-depth discussions, we finally introduce our FPGA-proven full-custom ASNoC.

• ETRI Journal
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• 제37권4호
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• pp.696-706
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• 2015

This paper presents an achievable secure videoconferencing system based on quantum key encryption in which key management can be directly applied and embedded in a server/client videoconferencing model using, for example, OpenMeeting. A secure key management methodology is proposed to ensure both a trusted quantum network and a secure videoconferencing system. The proposed methodology presents architecture on how to share secret keys between key management servers and distant parties in a secure domain without transmitting any secrets over insecure channels. The advantages of the proposed secure key management methodology overcome the limitations of quantum point-to-point key sharing by simultaneously distributing keys to multiple users; thus, it makes quantum cryptography a more practical and secure solution. The time required for the encryption and decryption may cause a few seconds delay in video transmission, but this proposed method protects against adversary attacks.

• Investigative Magnetic Resonance Imaging
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• 제23권4호
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• pp.328-340
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• 2019

Purpose: To generate phase images with free of motion-induced artifact and susceptibility-induced distortion using 3D radial ultrashort TE (UTE) MRI. Materials and Methods: The field map was theoretically derived by solving Laplace's equation with appropriate boundary conditions, and used to simulate the image distortion in conventional spin-warp MRI. Manufacturer's 3D radial imaging sequence was modified to acquire maximum number of radial spokes in a given time, by removing the spoiler gradient and sampling during both rampup and rampdown gradient. Spoke direction randomly jumps so that a readout gradient acts as a spoiling gradient for the previous spoke. The custom raw data was reconstructed using a homemade image reconstruction software, which is programmed using Python language. The method was applied to a phantom and in-vivo human brain and abdomen. The performance of UTE was compared with 3D GRE for phase mapping. Local phase mapping was compared with T₂* mapping using UTE. Results: The phase map using UTE mimics true field-map, which was theoretically calculated, while that using 3D GRE revealed both motion-induced artifact and geometric distortion. Motion-free imaging is particularly crucial for application of phase mapping for abdomen MRI, which typically requires multiple breathold acquisitions. The air pockets, which are caught within the digestive pathway, induce spatially varying and large background field. T₂* map, that was calculated using UTE data, suffers from non-uniform T₂* value due to this background field, while does not appear in the local phase map of UTE data. Conclusion: Phase map generated using UTE mimicked the true field map even when non-zero susceptibility objects were present. Phase map generated by 3D GRE did not accurately mimic the true field map when non-zero susceptibility objects were present due to the significant field distortion as theoretically calculated. Nonetheless, UTE allows for phase maps to be free of susceptibility-induced distortion without the use of any post-processing protocols.