• Journal of Institute of Control, Robotics and Systems
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• v.20 no.9
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• pp.964-970
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• 2014

In this study we have developed an anthropomorphic robot hand and arm by using tendon-tubes which can be used for people's everyday life as a robot's dynamic power transmission device. Most previous robot hands or arms had critical problem on dynamic optimization due to heavy weight of power transmission parts which placed on robot's finger area or arm area. In order to resolve this problem we designed light-weighted robot hand and arm by using tendon-tubes which were consisted of many articulations and links just like human's hand and arm. The most prominent property of this robot hand and arm is reduction of the weight of robot's power transmission part. Reduction of weight of robot's power transmission parts will allow us to develop energy saving and past moving robot hands and arms which can be used for artificial arms. As a first step for real development in this study we showed structural design and demonstration of simulation of possibility of a robot hand and arm by tendon-tube. In the future research we are planning to verify practicality of the robot hand and arm by applying sensing and controlling method to a specimen.

• Journal of Power Electronics
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• v.17 no.6
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• pp.1694-1706
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• 2017

Models and experiments for magnetic resonance coupling wireless power transmission (MRC-WPT) topologies such as the chain topology and branch topology are studied in this paper. Coupling mode theory based energy resonance models are built for the two topologies. Complete energy resonance models including input items, loss coefficients, and coupling coefficients are built for the two topologies. The storage and the oscillation model of the resonant energy are built in the time domain. The effect of the excitation item, loss item, and coupling coefficients on MRC systems are provided in detail. By solving the energy oscillation time domain model, distance enhancing models are established for the chain topology, and energy relocating models are established for the branch topology. Under the assumption that there are no couplings between every other coil or between loads, the maximum transmission capacity conditions are found for the chain topology, and energy distribution models are established for the branch topology. A MRC-WPT experiment was carried out for the verification of the above model. The maximum transmission distance enhancement condition for the chain topology, and the energy allocation model for the branch topology were verified by experiments.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.4 no.3
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• pp.18-29
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• 1993

In single mode fiber optic transmission systems(FOT's) operated at high modulation rates over long fiber spans, chromatic dispersion can produce distortion in the demodulated waveforms, resulting in intersymbol interference(ISI) in the received signal and a reduction of transmission system performance. In this paper, chromatic dispersion limitations for intensity modulation and direct detection(IM-DD) systems are studied by considering the effect of phase modulation to amplitude modulation (PM-AM) conversion noise. Laser phase noise conversion to amplitude noise due to fiber chromatic dispersion is analyzed by deriving the noise power spectral density. We first derive the noise power spectral density of the laser phase noise to intensity noise conver- sion. Next, also evaluate the system power penalty and the transmitter laser linewidth required to avoid PM-AM conversion noise penalties in long-haul nonregenerative transmission system using an external modulator and optical amplifiers. For such system with optical amplifiers, transmission sys- tem length is limited due to fiber chromatic dispersion, even if an ideal external modulator is used.

• Journal of the Korean Professional Engineers Association
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• v.19 no.4
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• pp.36-41
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• 1986

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.6
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• pp.1-8
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• 2009

Though the wireless ad-hoc network which is recently highly focused is power limited network, one of the main research topic is power saving. We propose a optimal power allocation strategy and derive the optimal power of the opportunistic transmission relays for minimum outage probability of the power limited network. It is shown that the proposed optimal power allocation has always better performance than that of the equal power allocation.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.58-58
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• 2002

Recently Many technologies of the P.L.N (Power Line Network) are introduced for an efficient communication. P.L.N transmits information using power line channel. A medical information transmission system is proposed in this paper for the effective transmission. The Power Line Networks have an advantage in low cost because it uses existent power line. It can be easily applied anywhere that a power line socket is available. But the power line channel is very noisy, because many electronic devices in generate electronic noise in modulated signals. This problem should be considered carefully in the design of medical information transmission system using P.L.N. The proposed system can be applied...I propose a telemedicine system using the power line network.

• Journal of Communications and Networks
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• v.15 no.5
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• pp.486-495
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• 2013

In this article, we suggest a two-dimensional genetic algorithm (GA) method that applies a cognitive radio (CR) decision engine which determines the optimal transmission parameters for multicarrier communication systems. Because a CR is capable of sensing the previous environmental communication information, CR decision engine plays the role of optimizing the individual transmission parameters. In order to obtain the allowable transmission power of multicarrier based CR system demands interference analysis a priori, for the sake of efficient optimization, a two-dimensionalGA structure is proposed in this paper which enhances the computational complexity. Combined with the fitness objective evaluation standard, we focus on two multi-objective optimization methods: The conventional GA applied with the multi-objective fitness approach and the non-dominated sorting GA with Pareto-optimal sorting fronts. After comparing the convergence performance of these algorithms, the transmission power of each subcarrier is proposed as non-interference emission with its optimal values in multicarrier based CR system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11C
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• pp.1059-1066
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• 2009

In this paper, we propose the precoder with superimposed pilots for orthogonal frequency-division multiple access (OFDMA) systems in order to enhance the transmission efficiency of the system and reduce peak-to-average power ratio (PAPR) which is the problem in OFDMA uplink. In wireless communication systems, the way to improve transmission efficiency is 1) to reduce bit error rate (BER) or 2) to increase data rate. In the proposed scheme, we design the precoder and superimposed pilots in the transmitter and use them in the receiver for increasing data rate, caused by the saved transmission bandwidth thanks to the superimposed pilots. In addition, we improve BER performance with the help of the frequency diversity gain caused by precoding. Also using superimposed pilots, we enhance the PAPR performance by increasing the average output power of the signal.

• 전기의세계
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• v.29 no.3
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• pp.185-192
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• 1980

It is revealed that duality and similarity between both capacitance and inductance systems coexist, and also that the former is more efficient than the latter in application viewpoints in time-invariant linear cases as far as both systems are concerned. This paper, using the similarity relation, proposes a new magnetics capacity concept similar to electrostatic capacity so that inductance systems may be interpreted as the corresponding capacitance systems. The new concept makes it convenient to analyze the both systems by unified approach. Finally an example demonstrates the applicability and convenience of the proposed method, through the analysis of capacitances and inductances on the transposed transmission line.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.7A
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• pp.542-549
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• 2005

In this paper, the optimal pump light power of optical phase conjugator (OPC) and the compensation characteristics of distorted WDM channel signals are numerically investigated, when the OPC with highly-nonlinear dispersion shifted fiber (HNL-DSF) not be placed at the mid-way of total transmission length. The total dispersion of former half section and latter half section is assumed to be same each other in this approach. It is confirmed that, in WDM transmission systems with OPC deviated from the mid-way, the pump light power for best compensation must be flexible selected depending on the OPC position. This optimal pump light power is gradually increased as the OPC is gradually closer to the receiver. Consequently, it is possible to establish the compensation system independent on the OPC position by setting optimal pump light power connected with the OPC position.