• 한국경영과학회지
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• 제31권3호
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• pp.41-51
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• 2006

Clustering is to group similar objects into clusters. Until now there are a lot of approaches using Self-Organizing feature Maps (SOFMS) But they have problems with a small output-layer nodes and initial weight. For example, one of them is a one-dimension map of c output-layer nodes, if they want to make c clusters. This approach has problems to classify elaboratively. This Paper suggests one-dimensional output-layer nodes in SOFMs. The number of output-layer nodes is more than those of clusters intended to find and the order of output-layer nodes is ascending in the sum of the output-layer node's weight. We un find input data in SOFMs output node and classify input data in output nodes using Euclidean distance. The proposed algorithm was tested on well-known IRIS data and TSPLIB. The results of this computational study demonstrate the superiority of the proposed algorithm.

• 대한산업공학회지
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• 제31권3호
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• pp.257-264
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• 2005

This paper suggests a heuristic algorithm for the clustering problem. Clustering involves grouping similar objects into a cluster. Clustering is used in a wide variety of fields including data mining, marketing, and biology. Until now there are a lot of approaches using Self-Organizing Feature Maps(SOFMs). But they have problems with a small output-layer nodes and initial weight. For example, one of them is a one-dimension map of k output-layer nodes, if they want to make k clusters. This approach has problems to classify elaboratively. This paper suggests one-dimensional output-layer nodes in SOFMs. The number of output-layer nodes is more than those of clusters intended to find and the order of output-layer nodes is ascending in the sum of the output-layer node's weight. We can find input data in SOFMs output node and classify input data in output nodes using Euclidean distance. We use the well known IRIS data as an experimental data. Unsupervised clustering of IRIS data typically results in 15 - 17 clustering error. However, the proposed algorithm has only six clustering errors.

• 한국콘텐츠학회논문지
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• 제9권1호
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• pp.123-130
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• 2009

일반적으로 다층퍼셉트론을 패턴인식 문제에 적용할 경우 클래스 당 하나의 출력 노드를 배정하고, 이 출력 노드의 인덱스가 입력 패턴의 클래스를 뜻하도록 한다. 이 논문에서는 이와 달리 다층퍼셉트론의 성능 향상을 위하여 클래스 당 출력노드 수를 증가시키는 방법을 제안한다. 두 개의 클래스 문제를 대상으로 클래스 발생확률이 동일하고 각 클래스 내에서 출력노드가 균일분포를 지닌다는 가정 하에, 이 방법의 효용성을 확률론적인 유도를 통하여 증명하였다. 그리고, 50개의 고립단어 인식의 시뮬레이션으로 출력노드를 증가 시킬 경우 성능이 향상됨을 확인하였다.

• 한국정보통신학회논문지
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• 제9권6호
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• pp.1288-1293
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• 2005

본 논문에서는 TDBM과 CMTEDD를 사용하여 다중출력조합디지털논리시스템 설계방법의 한가지를 제안하였다. 또한, CBDD와 CMTEDD를 기반으로 최종 조합디지털논리시스템 구성을 멀티플렉서를 사용하여 구현하였다. 제안한 방법은 기존의 방법에 비해 모듈사이의 내부결선을 효과적으로 줄일 수 있으며 입력변수의 쌍과 출력함수의 쌍에 의해 게이트 수를 줄일 수 있는 장점이 있다.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2006년도 추계 종합학술대회 논문집
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• pp.13-15
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• 2006

다층퍼셉트론을 패턴인식 문제에 적용하는 경우 대부분 하나의 클래스 당 하나의 출력노드를 할당한다. 이 논문에서는 class 당 출력노드 수를 증가시키는 경우에 다층퍼셉트론의 성능이 향상되는 지 고립단어 인식 문제의 시뮬레이션을 통하여 고찰하였다. 시뮬레이션 결과 출력노드 수가 하나인 경우보다 증가시킨 경우 더 나은 성능을 얻었다.

• 전기의세계
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• 제22권4호
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• pp.25-29
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• 1973

The computation of transmittances between arbitrary input and output nodes is of particular interest in the signal flow graph theory imput. The signal flow matrix [T] can be defined by [X]=-[T][X] where [X] and [Y] are input nose and output node matrices, respectively. In this paper, the followings are discussed; 1) Reduction of nodes by reforming the signal flow matrix., 2) Solution of input-output relationships by means of Gauss-Jordan reduction method, 3) Extension of the above method to the matrix signal flow graph.

• Journal of Power Electronics
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• 제16권5호
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• pp.1821-1832
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• 2016

This study presents a strategy using the synchronized output regulation method (SOR) for controlling inverters operating in stand-alone and grid-connected modes. From the view point of networked dynamic systems, SOR involves nodes with outputs that are synchronized but also display a desirable wave shape. Under the SOR strategy, the inverter and grid are treated as two nodes that comprise a simple network. These two nodes work independently under the stand-alone mode. An intermediate mode, here is named the synchronization mode, is emphasized because the transition from the stand-alone mode to the grid-connected mode can be dealt as a standard SOR problem. In the grid-connected mode, the inverter operates in an independent way, in which the voltage reference changes for generalized synchronization where its output current satisfies the required power injection. Such a relatively independent design leads to a seamless transfer between operation modes. The closed-loop system is analyzed in the state space on the basis of the output regulation theory, which improves the robustness of the design. Simulations and experiments are performed to verify the proposed control strategy.

• Journal of Communications and Networks
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• 제12권3호
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• pp.231-239
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• 2010

In cluster-based wireless sensor networks, the energy could be saved when the nodes that have data to transmit participate in cooperative multiple-input multiple-output (MIMO). In this paper, by making the idle nodes that have no data to transmit participate in the cooperative MIMO, it is found that much more energy could be saved. The number of the idle nodes that participate in the cooperative MIMO is optimized to minimize the total energy consumption. It is also found that the optimal number of all the nodes participating in cooperative communication does not vary with the number of nodes that have data to transmit. The proposition is proved mathematically. The influence of long-haul distance and modulation constellation size on the total energy consumption is investigated. A cooperative MIMO scheme with help-node participation is proposed and the simulation results show that the proposed scheme achieves significant energy saving.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권8호
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• pp.3823-3840
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• 2017

This paper analyzes the nodes deployment optimization problem in energy constrained wireless sensor networks, which multi-hop cooperative beamforming (CB) based cooperative-multi-input-single-output (CMISO) transmission is adopted to reduce the energy consumption. Firstly, we establish the energy consumption models for multi-hop SISO, multi-hop DSTBC based CMISO, multi-hop CB based CMISO transmissions under random nodes deployment. Then, we minimize the energy consumption by searching the optimal nodes deployment for the three transmissions. Furthermore, numerical results present the optimal nodes deployment parameters for the three transmissions. Energy consumption of the three transmissions are compared under optimal nodes deployment, which shows that CB based CMISO transmission consumes less energy than SISO and DSTBC based CMISO transmissions. Meanwhile, under optimal nodes deployment, the superiorities of CB based CMISO transmission over SISO and DSTBC based CMISO transmissions can be more obvious when path-loss-factor becomes low.

• ETRI Journal
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• 제36권4호
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• pp.564-571
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• 2014

Sphere decoding (SD) for multiple-input and multiple-output systems is a well-recognized approach for achieving near-maximum likelihood performance with reduced complexity. SD is a tree search process, whereby a large number of nodes can be searched in an effort to find an estimation of a transmitted symbol vector. In this paper, a simple and generalized approach called layer pruning is proposed to achieve complexity reduction in SD. Pruning a layer from a search process reduces the total number of nodes in a sphere search. The symbols corresponding to the pruned layer are obtained by adopting a QRM-MLD receiver. Simulation results show that the proposed method reduces the number of nodes to be searched for decoding the transmitted symbols by maintaining negligible performance loss. The proposed technique reduces the complexity by 35% to 42% in the low and medium signal-to-noise ratio regime. To demonstrate the potential of our method, we compare the results with another well-known method - namely, probabilistic tree pruning SD.