• KIPS Transactions on Computer and Communication Systems
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• v.2 no.2
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• pp.67-74
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• 2013

Approximate string matching problems have been studied in diverse fields. Recently, fast approximate string matching algorithms are being used to reduce the time and costs for the next generation sequencing. To measure the amounts of errors between two strings, we use a distance function such as the edit distance. Given two strings X(|X| = m) and Y(|Y| = n) over an alphabet ${\Sigma}$, the edit distance between X and Y is the minimum number of edit operations to convert X into Y. The edit distance between X and Y can be computed using the well-known dynamic programming technique in O(mn) time and space. The edit distance also can be computed using the Four-Russians' algorithm whose preprocessing step runs in $O((3{\mid}{\Sigma}{\mid})^{2t}t^2)$ time and $O((3{\mid}{\Sigma}{\mid})^{2t}t)$ space and the computation step runs in O(mn/t) time and O(mn) space where t represents the size of the block. In this paper, we present a parallelized version of the computation step of the Four-Russians' algorithm. Our algorithm computes the edit distance between X and Y in O(m+n) time using m/t threads. Then we implemented both the sequential version and our parallelized version of the Four-Russians' algorithm using CUDA to compare the execution times. When t = 1 and t = 2, our algorithm runs about 10 times and 3 times faster than the sequential algorithm, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.12
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• pp.2806-2811
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• 2013

New technologies such as multi-antenna and small cell were proposed as key technology for the next generation mobile system to cope with the explosively increasing mobile data traffic. In particular, heterogeneous mobile communication network which can improve spatial reuse factor by exploiting macro and small cells simultaneously is attracting attention. However, the heterogeneous network has a problem that the utilization of small cells becomes low because the transmit power of macro base stations is much higher than that of small base stations and then the probability that mobile stations are attached to the macro base stations becomes high. This problem is dominant in uplink. The concept of cell range expansion bias to mitigate the problem was proposed by 3GPP and the corresponding standardization is in progress. In this paper, we analyze the downlink performance of the heterogeneous mobile communication network based on a system level simulator with the cell range expansion bias in terms of average cell spectral efficiency.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.3
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• pp.527-533
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• 2018

Recently, the device-to-device (D2D) communication has been conceived as the key technology for the next-generation mobile communication systems. The neighbor discovery in which the nearby users are found, is essential for the proper operation of the D2D communication. In this paper, we propose new neighbor discovery scheme based on deep learning technology which has gained a lot of attention recently. In the proposed scheme, the neighboring users can be found using the uplink pilot transmission of users only, unlike conventional neighbor discovery schemes in which direct pilot communication among users is required, such that the signaling overhead can be greatly reduced in our proposed scheme. Moreover, the neighbors with different proximity can also be classified accordingly which enables more accurate neighbor discovery compared to the conventional schemes. The performance of our proposed scheme is verified through the tensorflow-based computer simulations.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.86-86
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• 2018

본 연구는 한국의 도시재생과 스마트 물 관리의 정책 분석을 위하여 도시재생과 스마트 물 관리의 등장 배경, 주요 현안 및 연계성을 모색하고 도시재생방안으로서 스마트 물 관리체계의 가능성을 검토하는 것을 목적으로 한다. 1950년대의 도시재건(Urban Reconstruction)과 1970~80년대의 도시재개발(Urban Renewal, Urban Redevelopment) 등의 정비 사업은 물리적 환경정비에 초점을 맞추었다. 그러나 1990년대 환경문제가 세계적 이슈로 등장하면서 교외지역 난개발 문제에 대한 대응책이 필요하게 되었고 도시의 물리 환경적, 산업 경제적, 사회 문화적 측면을 부흥시키는 도시재생 접근법이 출현하였다. 한국 정부는 2017년부터 시작한 '도시재생 뉴딜사업'의 일환으로 스마트 기술을 적용한 도시재생사업을 통해 스마트도시 선도국가 도약과 세계적 흐름에 부합하는 도시성장을 기대하고 있다. 1980년대 초 등장한 스마트 기술은 2000년대 들어와 스마트 도시, 스마트 인프라, 스마트 그리드 등의 분야로 확대, 진보하였다. 물 분야의 스마트 기술은 2009년 스마트워터그리드 이니셔티브(Smart Water Grid Initiative)의 발족과 함께 IBM, CISCO, Intel 등의 IT 기반 물 관리 워킹그룹 형성, Suez, Veolia, Siemens 등 수처리 기업의 스마트워터그리드 분야 진출 모색과 함께 발전하기 시작하였다. 이후 2012년 유엔 스마트 물 관리 포커스 그룹(ITU-T SG 5)의 스마트 물 관리 표준화 연구가 착수되었고 한국은 국토교통부 건설교통기술 연구 개발사업 중 하나로 스마트 물 관리 장기 연구 사업을 시작하였다. 스마트 물 관리는 수자원 및 상하수도 관리의 효율성 제고를 위하여 스마트 미터, 센서, 디지털지도제작 등 ICT를 이용한 차세대 물 관리시스템이라고 정의할 수 있다. 구체적인 대상 분야를 고려한다면 하천수, 우수, 지하수, 하폐수처리수, 해수담수 등 다양한 수자원의 관리, 물의 생산과 수송, 사용한 물의 처리 및 재이용 등 물 관리 전 분야를 포함한다. 그러나 스마트 물 관리의 용어와 개념을 처음으로 도입한 미국 등 선진국과 관련기업들은 스마트 물 관리를 '스마트 워터 미터, 센서, 첨단 모델링, 수문 지도제작, 스마트 관개농업, 자동화 로봇 등 다양한 기술을 통합적으로 운영하는 지능적인 수자원 관리를 위한 정보네트워크'로 정의한다. 일찍이 도시재생으로의 패러다임 전환을 실시한 영국 및 일본과 달리 한국의 도시재생은 개념, 구성요소, 범위, 사업방식 등의 여러 가지 측면에서 아직 형성단계에 있다. 또한 한국의 스마트 물 관리 논의는 개념정립 측면에서 심층적 논의가 거의 부재하였다. 기존의 논의들은 수자원 혹은 상하수도서비스 분야에서의 연구결과와 기술개발성과를 기계적으로 적용하고 확대하는 측면만을 부각시켰다. 그러나 이와 같은 스마트 물 관리에 대한 논의는 정보통신기술과 물 관리 서비스를 단편적으로 연결하고 적용범위를 제한할 수도 있다는 점에서 한계성이 있다. 본 연구는 국내외 문헌검토를 바탕으로 한국의 도시재생과 스마트 물 관리의 정책을 분석하고 지금까지 별개로 간주된 두 개념의 장점을 융합하여 향후 지속가능한 도시개발 사업으로서의 가능성을 검토하고자 한다.

• Applied Chemistry for Engineering
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• v.33 no.1
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• pp.58-63
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• 2022

Graphite has been used as an anode material for lithium-ion batteries for the past 30 years due to its low de-/lithiation voltage, high theoretical capacity of 372 mAh/g, low price, and long life properties. Recently, all-solid-state lithium-ion batteries (ASSLB), which are composed of inorganic solid materials with high stability, have received great attention as electric vehicles and next-generation energy storage devices, but research works on graphite that works well for ASSLB systems are insufficient. Therefore, we induced the performance improvement of ASSLB anode electrode graphite material by removing the amorphous carbon present in the carbon material surface, acting as a resistive layer from the graphite. As a result of X-ray diffraction (XRD) analysis using heat treated graphite in air at 400, 500, and 600 ℃, the full width at half maximum (FWHM) at (002) peak was reduced compared to that of bare graphite, indicating that the crystallinity of graphite was improved after heat treatment. In addition, the discharge capacity, initial coulombic efficiency (ICE) and cycle stability increased as the crystallinity of graphite increased after heat treatment. In the case of graphite annealed in air at 500 ℃, the high capacity retention rate of 331.1 mAh/g and ICE of 86.2% and capacity retention of 92.7% after 10-cycle measurement were shown.

• Journal of KIISE:Computing Practices and Letters
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• v.8 no.1
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• pp.88-95
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• 2002

In recent years, the security of hardware and software systems is one of the most essential factor of our safe network community. As elliptic Curve Cryptosystems proposed by N. Koblitz and V. Miller independently in 1985, require fewer bits for the same security as the existing cryptosystems, for example RSA, there is a net reduction in cost size, and time. In this thesis, we propose an efficient hardware architecture of underlying field arithmetic processor for Elliptic Curve Cryptosystems, and a very useful method for implementing the architecture, especially multiplicative inverse operator over GF$GF (2^m)$ onto FPGA and futhermore VLSI, where the method is based on optimized unit operation components. We optimize the arithmetic processor for speed so that it has a resonable number of gates to implement. The proposed architecture could be applied to any finite field $F_{2m}$. According to the simulation result, though the number of gates are increased by a factor of 8.8, the multiplication speed We optimize the arithmetic processor for speed so that it has a resonable number of gates to implement. The proposed architecture could be applied to any finite field $F_{2m}$. According to the simulation result, though the number of gates are increased by a factor of 8.8, the multiplication speed and inversion speed has been improved 150 times, 480 times respectively compared with the thesis presented by Sarwono Sutikno et al. [7]. The designed underlying arithmetic processor can be also applied for implementing other crypto-processor and various finite field applications.

• Journal of the Korean Society of Radiology
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• v.18 no.3
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• pp.187-201
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• 2024

Osteoporosis is a major health issue globally, often remaining undetected until a fracture occurs. To facilitate early detection, deep learning (DL) models were developed to classify osteoporosis using abdominal computed tomography (CT) scans. This study was conducted using retrospectively collected data from 3,012 contrast-enhanced abdominal CT scans. The DL models developed in this study were constructed for using image data, demographic/clinical information, and multi-modality data, respectively. Patients were categorized into the normal, osteopenia, and osteoporosis groups based on their T-scores, obtained from dual-energy X-ray absorptiometry, into normal, osteopenia, and osteoporosis groups. The models showed high accuracy and effectiveness, with the combined data model performing the best, achieving an area under the receiver operating characteristic curve of 0.94 and an accuracy of 0.80. The image-based model also performed well, while the demographic data model had lower accuracy and effectiveness. In addition, the DL model was interpreted by gradient-weighted class activation mapping (Grad-CAM) to highlight clinically relevant features in the images, revealing the femoral neck as a common site for fractures. The study shows that DL can accurately identify osteoporosis stages from clinical data, indicating the potential of abdominal CT scans in early osteoporosis detection and reducing fracture risks with prompt treatment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4C
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• pp.391-399
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• 2006

We propose a novel low complexity video encoder, at the expense of a complex decoder, where video frames are intra-coded periodically and frames in between successive intra-coded frames are coded efficiently using a proposed irregular binning technique. We investigate a method of forming an irregular binning which is capable of quantizing any value effectively with only small number of bins, by exploiting the correlation between successive frames. This correlation is additionally exploited at the decoder, where the quality of reconstructed frames is enhanced gradually by applying POCS(projection on the convex sets). After an image frame is reconstructed with the irregular binning information at the proposed decoder, we can further improve the resulting quality by modifying the reconstructed image with motion-compensated image components from the neighboring frames which are considered to contain image details. In the proposed decoder, several iterations of these modification and re-projection steps can be invoked. Experimental results show that the performance of the proposed coding scheme is comparable to that of H.264/AVC coding in m mode. Since the proposed video coding does not require motion estimation at the encoder, it can be considered as an alternative for some versions of H.264/AVC in applications requiring a simple encoder.

• Smart Media Journal
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• v.9 no.2
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• pp.51-62
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• 2020

Starting with the "Smart Grid National Road Map" in 2010, the Smart Grid 2030 was introduced through the basic plan and implementation plan of the intelligent power grid with the goal of building the world's first national smart grid. In this paper, we intend to build a power domain ontology based on the power business platform based on the upper and lower conceptual models of the "Smart Grid Interoperability Standard Framework and Roadmap", the standard of implementation plan. Ontology is suitable for expressing and utilizing the smart grid conceptual model because it considers hierarchical structure as knowledge defines the properties of entities and relationships between entities, but there is no research related to them. Therefore, in this paper, the upper ontology was defined as a major category for smart grid-related fields, and the lower ontology was defined as detailed systems and functions for the upper ontology to construct the ontology. In addition, scenarios in various situations that could occur in the power system were constructed and significant inference results were derived through inference engines and queries.

• Journal of Convergence for Information Technology
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• v.11 no.6
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• pp.262-269
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• 2021

The Ministry of National Defense is re-establishing the role of the Army in accordance with the defense reform and is promoting the Warrior Platform, a next-generation individual combat system. The Warrior Platform project is divided into three stages and is being promoted. In the first stage, the quality and performance of individual items are improved, in the second stage, items between system development are integrated, and in the third stage, the combat capability is maximized by developing an integrated unit weapon system. In this paper, detailed sub-items for the five essential required competencies (survival, lethality, mobility, sustainability, Communication) that are considered for building an effective warrior platform are presented. We also present a plan that can be used to prepare a specific master plan for the Army's Warrior Platform project by using Analytic Hierarchy Process(AHP) and selecting the priority of the five required capabilities and detailed sub-items for different unit types. As a result of analyzing the priorities of the four types of units with different mission types, we find that there are differences for each unit. These results are expected to be used as useful reference materials for setting the future direction for the development of warrior platform.