수중 통신을 위한 일반화된 처프 대역 확산 기법

한상만(Sangman Han),김진원(Jinwon Kim),서보근(Bogeun Seo),이호준(Hojun Lee) 호서대학교 공업기술연구소 2024 공업기술연구 논문집 Vol.43 No.1

본 논문에서는 chirp spread spectrum (CSS) 기법의 전송률을 높이기 위해서 다양한 변조 차수를 가질 수 있는 generalized-CSS (G-CSS) 기법을 제안한다. 기존의 CSS 기법은 상향 처프 또는 하양 처프로 변조하는 방법으로 제한적인 변조차수를 가지기 때문에 전송률이 낮다는 한계를 가지게 된다. 제안하는 G-CSS 기법은 심볼의 시작 및 끝 시점에 대해 서로 다른 변조 차수에 따라 주파수 빈을 설정하고, 전송하고자 하는 비트에 따라 시작 주파수와 끝 주파수로 끝나는 처프 신호를 할당하여 변조한다. 제안한 G-CSS 기법은 다양한 변조 차수로 설계가 가능하며 시스템에서 요구하는 전송률에 따라 신호를 설계하여 전송할 수 있다. 전산 모의실험을 통해 기존의 기법과 제안한 기법이 동일한 전송률을 가칠 때에 통신 성능을 분석하였으며 제안한 방법이 기존의 방법보다 bit error rate (BER) 성능의 결과가 약 2배 성능이 향상된 것을 보였다. This paper proposes a generalized-chirp spread spectrum (G-CSS) modulation scheme, which is able to adjust various modulation orders to increase transmission rate of the conventional chirp spread spectrum (CSS). The conventional CSS uses up-chirp or down-chirp for modulation, which have limited modulation orders, resulting in a lower transmission rate. The proposed G-CSS sets frequency bins according to different modulation orders at the start and end points of the symbol. It modulates by assigning a chirp signal with assigned start and end frequencies based on the bits to be transmitted The proposed G-CSS can be designed with various modulation orders, allowing the system to be tailored to meet the required transmission rates. Through computational simulations, the bit error rate (BER) performances of the proposed G-CSS were compared with the conventional CSS with the same transmission rate, and the BER performances of the proposed G-CSS had twice better than that of the conventional CSS.

연구논문 : 두산 "산" 소주

한상만 ( Sang Man Han ),하영원 ( Young Won Ha ) 한국마케팅학회 2002 ASIA MARKETING JOURNAL Vol.4 No.3

평면비대칭을 고려한 추가 감쇠기가 있는 시스템의 간략화된 지진응답해석

한상을(Han Sang-Eul),최문호(Choi Moon-Ho),공석환(Kong Seok-Hwan) 대한건축학회 2008 大韓建築學會論文集 : 構造系 Vol.24 No.12

This study investigates the effectiveness of proposed modal analysis method using the pseudo-force to deal with supplemental damping in the seismic analysis of elastic systems. On this study, the one-way asymmetric systems are considered because these will undergo lateral and torsional motion simultaneously due to supplemental damping and stiffness eccentricities. For the purpose of this study, the analysis is performed with the consideration of large range of system parameters, such as asymmetric of system and distribution of supplemental damping. And, the CPU running times are compared to investigate the effect of additional procedure on proposed methods. Finally, these proposed methods are applied to a three-story one-way asymmetric building with supplemental damping on each floor. These analytical results are compared with those obtained by direct integration method and conventional approximate method, which neglects the off-diagonal terms of the transformed damping matrix. It is found that the proposed methods can significantly improve the accuracy of the analytical results compared to conventional approximate method on large range of system parameters although it need a little additional analysis time.

네트워크외부성이 소비자 선택행동에 미치는 영향에 관한 연구: 디지털카메라를 중심으로

한상만 ( Sang Man Han ),손용석 ( Yong Seok Sohn ),이영승 ( Young Seung Lee ) 한국소비자학회 2004 소비자학연구 Vol.15 No.3

Consumers are supposed to consider the intrinsic value incurring from multi-attribute of the product than any other in a decision making process. However there are many products with the value which is more than the intrinsic value, as the network effect grows. Therefore, it is an important issue to take a deep consideration into the network externalities as well as the intrinsic value of products under the purchasing situation. This research is to exam the network externalities when consumers make choice of a digital camera. Do the network externalities have an effect on making-decision process? In general, it is said that the network externalities have some features which we want to make sense those. We would draw a comparison between the intrinsic values and the network externalities through consumers` choice behaviors.

SNS 빅데이타를 사용한 예측집단(Predictable Cluster) 특성 연구

한상만 ( Sangman Han ),옥경영 ( Kyungyoung Ohk ) 한국소비자학회 2013 소비자학연구 Vol.24 No.2

본 연구는 SNS 사회적 네트워크에서 보다 긴밀한 관계를 바탕으로 형성된 소비자 클러스터인 하위네트워크 (sub-network)들 중에서 정보 확산의 최종 결과를 예측하는데 핵심이 되는 하위네트워크를 예측집단(predictable cluster)로 선정하고, 네트워크적 방법론을 사용하여 이 예측집단의 네트워크적 특성을 살펴보고자 하였다. 이를 위해 우리나라 SNS 사이트의 빅데이타를 사용하여 이 사이트에서 나타나는 사회적 네트워크를 도출하고 이 네트워크 에서 발생하는 정보 확산을 예측하기위한 예측집단인 하위집단을 선정하기위해 사회적 네트워크에서의 총확산과 개별하위네트워크 확산간의 상관관계를 분석하였다. 2개의 상관관계 분석을 바탕으로 예측집단(predictable cluster)을 선정하고 이들의 네트워크적 특성을 분석하였으며, 또한 이 예측집단의 네트워크에서의 정보 확산 특성과 정보수용 특성을 분석하였다. 그 결과, 먼저, 사회적 네트워크에서 추출된 100개의 하위네트워크들 중에서 예측집단(predictable cluster)로 선정된 하위네트워크들의 확산 특성에서는 q값, takeoff시점, peak시점이 유의하게 나타났다. 이것은 예측집단 (predictable cluster)으로 선정된 하위네트워크들은 q값이 작아질수록 100개 하위네트워크들의 총확산과 상관 관계가 높아져 전체 확산을 예측하기에 적절하며, 또한 takeoff시점은 짧을수록, peak 시점은 길수록 예측집단 (predictable cluster)의 특성이 더 높게 나타나고 있다는 것을 알 수 있었다. 다음으로, 예측집단(predictable cluster)으로 선정된 하위네트워크들의 수용 특성에서는 수용양과 유의한 차이가 있는 것으로 나타났다. 이것은 예측집단(predictable cluster)으로 선정된 하위네트워크들의 수용양이 클수록 100개 하위네트워크들의 총확산이 더높아지는 것으로, 총확산의 성공적인 양적 증가를 예측하는 방향으로 예측집단(predictable cluster)들의 특성이 나타나는 것이라 할 수 있다. 이상의 연구결과를 통해 몇 가지 시사점을 도출하였으며, 한계점도 제시하였다. In this study, the authors attempt to explore the existence of a predictable cluster and identify the properties of the predictable cluster. For this purpose, we first select a certain number of individuals randomly and identify their local networks. Each selected individual and his/her local network becomes a sub-network in a large network of the total population. Then, we select those sub-networks whose adoption behaviors correlates highly with the total population. And, we run a split-half test to investigate whether those selected sub-networks performs well in predicting the adoption behavior of the total population. Finally, we identify the properties of those selected sub-networks-we call the selected sub-network “predictable cluster”-with respect to the network characteristics following the social network theory. For measuring the property of sub-network in this study, we used four network indexes which are path length, clustering coefficient, betweenness centrality, and closeness centrality. Path Length is geodesic distance from node i to node j. Clustering coefficient is the proportion of number of triangles in the network-sets of three nodes each of which is connected to each of the others. Betweeness centrality is the proportion of all geodesics between pairs of other nodes that include this node. And, closeness centrality is the number of other nodes divided by the sum of all distance between the node and all others. In particular, we show in this study the process of identifying predictable clusters by social network approach. The major findings of this study are as follows. First, the greater the q-value or peak time, the greater the possibility the sub-network becomes a predictable cluster. Second, the smaller takeoff time, the greater the possibility the sub-network becomes a predictable cluster. Third, the greater the adoption volume, the greater the possibility the sub-network becomes a predictable cluster. The implication of this study is that predictive clusters can be a reliable predictor of overall information diffusion, and by identifying the predictable clusters, managers can develop more efficient communication strategy in the early time of the diffusion process. Limitations and future directions are discussed.

무요소의 적응적 세분화 방법을 이용한 국부화문제의 해석

한상을(Han Sang-Eul),이상주(Lee Sang-Joo),주정식(Joo Jung-Sik) 대한건축학회 2008 大韓建築學會論文集 : 構造系 Vol.24 No.3

The Meshfree method is a method used to establish a system of algebraic equations for the whole problem domain without using predefined mesh for the domain discretization. Point interpolation method is based on combination of radial and polynomial basis functions. Introducing of radial basis functions overcomes possible singularity problem. Furthermore, the interpolation function is applicable for all points scattered over in influence domain and thus shape functions are of delta function property, which makes the implementation of essential boundary conditions much easier than the meshfree methods based on the moving least-squares approximation. In this study, an adaptive node generation procedure in the radial point interpolation method is proposed. Since we set the initial configuration of nodes by subdivision of background cell, abrupt changes of inter-nodal distance between higher and lower error regions are unavoidable. This unpreferable nodal spacing induces additional errors. To obtain the smoothy nodal configuration, it's regenerated by local Delaunay triangulation algorithm. This technique was originally developed to generate a set of well-shaped triangles and tetrahedra. In order to evaluate the error estimation technique, cantilever type plate was investigated. To demonstrate the performance of proposed scheme, the results of making optimal nodal configuration with adaptive refinement method are investigated for stress concentration problems.

공간구조물의 비선형 탄소성 후좌굴해석에 관한 연구

한상을(Han Sang-Eul),이경수(Lee Kyoung-Su) 대한건축학회 2007 大韓建築學會論文集 : 構造系 Vol.23 No.12

In this study, a method for large deformation elastic-plastic analysis of space frame is presented. The method is based on large deformation formulation, which was developed initially for elastic systems, and is extended herein to include elasto-plastic effect. The method is based on an Eulerian formulation, which takes into consideration the effects of large joint translations and rotations. Local member force-deformation relationships are based on the beam-column approach, and the change in member chord lengths caused by axial strain and flexural bowing are taken into account. The effect of axial force of member on bending and torsional stiffness, and on plastic moment capacity, is included in the analysis. The material is assumed to be ideally elasto-plastic, and yielding is considered to be concentrated at member ends in the form of plastic hinges. The arc length approach is applied to trace the post-buckling range of elastic and elasto-plastic problems. Four numerical examples are presented which indicate that the method of analysis is highly accurate in predicting large deformation, buckling and post-buckling of elasto-plastic response of structures.

가상점성감쇠요소 도입에 의한 막구조의 형상탐색에 관한 연구

한상을(Han Sang-Eul),이경수(Lee Kyong-Soo),김정화(Kim Jung-Hwa) 대한건축학회 2007 大韓建築學會論文集 : 構造系 Vol.23 No.11

In shape-finding process of membrane structure by dynamic relaxation method, three-node triangular membrane elements, the finite elements, are generally used. But serious changes of curvature in many membrane structures can make the mesh distortion. As a result, the final form of the membrane is not appropriate for the patterning and the stress analysis. To solve these problems, the viscous damping element is introduced to control the mesh distortion. It is placed at three sides of a triangular membrane element and the nodal force, residual force, can be controled by the damping force. Also, it does not prevent the convergence of residual force. The damping element is applied to various models to evaluate the improvement of mesh distortion and it is verified that the introduction of viscous damping element can control the mesh distortion, efficiently.

비고전적 감쇠를 가지는 구조 시스템의 지진응답해석

한상을(Han Sang-Eul),최문호(Choi Moon-Ho) 대한건축학회 2008 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.28 No.1(구조계)

This study investigates the effectiveness of proposed modal analysis method to deal with non-classical damping in the seismic analysis of elastic systems. On this study, the three-story one-way asymmetric building with supplemental damping on each floor is considered because these has non-classical damping due to damping. For the purpose of this study, the analysis is performed and compared to estimate the accuracy. Then the CPU running times are compared to confirm the effect of additional procedure on proposed methods. It is found that the proposed methods can significantly improve the accuracy of the analytical results compared to conventional approximate method although it need a little additional analysis time.

철원지역에서 재배한 양마 (Kenaf, Hibiscus cannabinus L.)의 재식거리와 품종, 수확시기에 따른 건물수량 및 사료성분의 변화

한상은(Sang Eun Han),성경일(Kyung Il. Sung),조동하(Dong Ha Cho),김성무(Cheng Wu Jin),김병완(Byong Wan Kim) 한국초지조사료학회 2006 한국초지조사료학회지 Vol.26 No.4

본 연구는 양마 3품종을 재식거리, 품종 및 수확시기에 따른 건물수량과 사료성분의 변화를 검토하고자 강원도 철원지역에서 2005년 5월 20일부터 2005년 9월 12일까지 수행되었다. 시험배치는 3반복 분할구 배치로 주구는 재식거리와 수확시기를, 세구는 양마 3품종(Dowling, Everglade 및 Tainung)을 배치했으며, 결과를 요약하면 다음과 같다. 생육일수에 따른 건물생산량은 93일까지는 재식거리가 10×10㎠ 구에서 높게 나타났다. 품종별 건물생산량에서는 모든 품종이 생육시기가 진행됨에 따라 건물수량이 높아지는 경향을 보였고, 특히 Dowling이 모든 수확시기에서 가장 높은 건물생산량을 보였다. 조단백질 함량은 생육일수가 길어짐에 따라 감소하는 경향을 보였다. 특히, 생육 중기(생육일수 84일)을 기준으로 생육초기에는 조단백질 함량은 큰 차이를 나타내지 않았지만, 10×20㎠ 구에서 다소 높게 나타났다. 품종별로는 Dowling의 조단백질 함량이 다소 높은 것으로 조사되었으나, 큰 차이는 나타내지 않았다. 재식거리 및 품종에 따른 NDF와 ADF 함량의 차이는 조사된 3 품종 공히 생육시기가 지나감에 따라 다소 증가하는 경향을 보였지만, 큰 유의적 차이는 나타나지 않았다. 이상의 결과를 종합해 보면, 양마는 우리나라 중북부 지방에서 훌륭한 사료작물로서의 가능성이 검증되었고, 특히 Dowling 품종이 재식거리 10×10㎠로 파종하여 104일째 수확했을 때 가장 좋은 건물생산량과 품질을 보여주었다. This study was conducted to evaluate the dry matter yield and forage quality of Kenaf in relation to planting density and growing days in Cheorwon area from 20 May to 12 September in 2005. The experiment was laid out in a split plot design with three replications. The main plots consisted of planting density and growing days with three cultivars of Kenaf as sub-plots; Dowling, Everglade and Tainung. The results obtained were summarized as follows. The dry matter yield increased until 92 days after planting at 10×10㎠ planting density, but decreased after the day. The dry matter yield increased with maturity in all three cultivars, especially Dowling showed the highest dry matter yield at each harvest time. The Crude Protein (CP) contents of all three cultivars decreased with maturity. Especially, the decrease in the CP contents was greater in the early stage than in the late stage. The planting density did not affect the CP contents, even though they are little higher in 10×20㎠ planting density. The higher CP contents were observed in Dowling, which is not significant. No difference in the Neutral detergent fiber (NDF) and Acid detergent fiber (ADF) contents was observed in the planting density and cultivar, although the increasing tendency was found with maturity. These results suggest that Kenaf can be a good potential forage crop in the northern area of Korea, especially Dowling showed the great dry matter yield and forage quality when harvested on Day 104 at 10×20㎠ planting density.