• Journal of KIISE:Computer Systems and Theory
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• v.33 no.1_2
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• pp.62-68
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• 2006

The important arithmetic operations over finite fields include multiplication and exponentiation. An exponentiation operation can be implemented using a series of squaring and multiplication operations over GF($2^m$) using the binary method. Hence, it is important to develop a fast algorithm and efficient hardware for multiplication. This paper presents an efficient bit-serial systolic array for MSB-first multiplication in GF($2^m$) based on the polynomial representation. As compared to the related multipliers, the proposed systolic multiplier gains advantages in terms of input-pin and area-time complexity. Furthermore, it has regularity, modularity, and unidirectional data flow, and thus is well suited to VLSI implementation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.7
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• pp.1239-1247
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• 2015

In frequency-division duplex (FDD) massive multiple-input multiple-output (MIMO) system, the computational complexity of downlink channel estimation is proportional to the number of antennas at a base station. Therefore, effective channel estimation techniques may have to be studied. In this paper, novel channel estimation algorithms using adaptive techniques such as Kalman and least mean square (LMS) filters are proposed in a channel model with temporal and spatial correlation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.4A
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• pp.386-393
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• 2010

In this paper, we analyse HARQ scheme that utilizes symbol mapping diversity (SMD) techniques such as MDSM and CORE. The exploitation feasibility of MDSM and CORE is evaluated in the perspective of system complexity and storage capacity as we consider a BICM system based on 3GPP LTE standards and multipath fading channels. Also, a simple method which obtains SMD effects by circularly shifting bit-block in a codeword is proposed. The experimental results performed in BICM-OFDM systems with single antenna as well as multiple antennas show that frame error rate of the proposed method is close to that of CORE while having lower complexity.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2004.03a
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• pp.475-479
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• 2004

위성에서 감지되는 조간대 원격 반사도는 함수율, 퇴적상, 지형과 생물체 등의 영향에 의해 결정된다. 따라서 다른 환경요인을 제거하지 않고 위성자료 값을 분류하여 퇴적상과 비교한다면 좋은 결과를 얻을 수 없다. 하지만 퇴적상과 다른 환경요인은 관계가 복잡하고 미묘하게 얽혀있기 때문에 위성 자료 값에서 정량적으로 분리하거나 고려하는 것은 매우 어렵다. 특히 mud flat의 조류로나 세곡 부분은 배수구배의 발달로 인해 표층이 빠르게 마르게 되어 매우 높은 광학 반사도를 보이고 이는 sand가 우세한 지역의 높은 광학반사도와의 구별을 어렵게 만든다. 따라서 본 연구에서는 위성자료의 원격반사도 값만으로 조간대의 표층 퇴적상을 분류할 경우 에러가 발생할 수 있는 이러한 문제를 해결하기 위하여 조간대 texture와 표층 퇴적상과의 관계를 파악하고자 한다. 6.6 m 해상도를 갖는 EOC 자료를 이용하여 조류로의 형태와 밀도를 알아내고, 현장에서 샘플 된 입도 자료를 분석하여 비교함으로서 상관관계를 알아보고자 한다. mud flat의 경우, 대부분 복잡한 texture 구조를 갖고 밀도가 매우 높게 나타났으며 mixed flat 지역에서는 직선 구조를 갖는 큰 조류로가 발달하며 일부지역에서는 표면수가 잔존함에 의해 조간대에서 가장 어둡게 나타났다. 반면 sand shoal 이나 chenier 등과 같이 sand의 함량이 매우 높은 곳에서는 지형이 높아 함수율이 매우 낮아 높은 광학 반사도를 보임을 알 수 있었다.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.1
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• pp.23-32
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• 2011

In this paper, we develop a method for generating thumbnail images at hybrid domain combined the spatial domain and transform domain. The proposed method generates a pixel of a thumbnail image by adding a DC value of residual transform coefficients and an average value of an estimate block. For effectively calculating average values of estimate blocks, we propose a method for reconstructing the boundary pixels of a block. In comparison to the conventional method of decoding the bit stream then scaling down the decoded images, the developed method reduces the complexity by more than 60% while producing identical thumbnail images.

• Journal of IKEEE
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• v.16 no.4
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• pp.316-321
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• 2012

In this paper, we study the energy-efficient deployment strategy for micro base station (BS) in wireless cellular systems. Firstly, we formulate a general problem pertaining to total energy consumption minimization with the requirement of area spectral efficiency (ASE). We start from an observation about the correlation between the area covered by an additional micro BS and the increment of ASE. Under such an observation, we propose an efficient greedy micro BS deployment algorithm. Simulations show that the proposed deployment algorithm can deploy micro BSs with a slight performance reduction comparing with the optimal solution.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.9
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• pp.39-45
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• 2004

A design method is proposed for the sequence detection with fixed decision delay with less hardware complexity using the concept of the Voronoi diagram and its dual, the Delaunay tessellation. This detector design is based on the Fixed Delay Tree Search (FDTS) detection. The FDTS is a computationally efficient sequence detection algerian and has been shown to achieve near-optimal performance in the severe Intersymbol Interference (ISI) channels when combined with decision feedback equalization and the appropriate channel coding. In this approach, utilizing the information contained in the Voronoi diagram or equivalently the Delaunay tessellation, the relative location of the detector input sequence in the multi-dimensional Euclidean space is found without any computational redundancy, which leads to a reduced complexity implementation of the detector.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.1A
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• pp.44-49
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• 2008

Recently, a so called orthogonal spatial multiplexing(OSM) scheme was presented which allows simple maximum likelihood decoding at the receiver with single phase feedback In this paper, by serially concatenating this scheme by a linear precoder, a new closed-loop SM scheme is proposed for two transmit arid two receive antennas. By computer simulation results, we show that the proposed scheme outperforms the conventional SM and OSM. For the proposed code, we also propose a new simple decoding algorithm which leads to a greatly reduced decoding complexity compared with the ML receiver without any loss of error performance.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.1
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• pp.69-79
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• 2012

In this paper, we restrict the case as m odd, n=mk, and propose and explicitly exhibit the architecture of a new parallel multiplier over the field GF($2^m$) with a type k Gaussian period which is a subfield of the field GF($2^n$) implements multiplication using the parallel multiplier over the extension field GF($2^n$). The complexity of the time and area of our multiplier is the same as that of Reyhani-Masoleh and Hasan's multiplier which is the most efficient among the known multipliers in the case of type IV.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.2
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• pp.469-478
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• 2010

This paper proposes the effective shape descriptor for 3D foot pose estimation. To reduce processing time, silhouette-based foot image database is built and meta information which involves the 3D pose of the foot is appended to the database. And we proposed a modified Centroid Contour Distance whose size of the feature space is small and performance of pose estimation is better than the others. In order to analyze performance of the descriptor, we evaluate time and spatial complexity with retrieval accuracy, and then compare with the previous methods. Experimental results show that the proposed descriptor is more effective than the previous methods on feature extraction time and pose estimation accuracy.