• ETRI Journal
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• v.42 no.1
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• pp.26-35
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• 2020

Herein, we consider uplink multiuser massive multiple-input multiple-output systems when multiple users transmit information symbols to a base station (BS) by applying simple space-time block coding (STBC). At the BS receiver, two detection filters for each user are used to detect the STBC information symbols. One of these filters is for odd-indexed symbols and the other for even-indexed symbols. Using constrained output variance metric minimization, we first derive a special relation between the closed-form optimal solutions for the two detection filters. Then, using the derived special relation, we propose a new blind adaptive algorithm for implementing the minimum output variance-based optimal filters. In the proposed adaptive algorithm, filter weight vectors are updated only in the region satisfying the special relation. Through a theoretical analysis of the convergence speed and a computer simulation, we demonstrate that the proposed scheme exhibits faster convergence speed and lower steady-state bit error rate than the conventional scheme.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.1
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• pp.88-95
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• 2011

In this paper, a new standby-mode control method for multiple output switching-mode power-supply is suggested, which uses the control signal of the feedback compensator of the inner loop in the linear voltage regulator located at the transformer secondary side, as the load current information. Conventional method has a problem that standby mode occurs depending only on the load condition of the main controller output, which makes the other secondary side output very inaccurate by burst mode operation. The proposed method detects all the load current information and operates in burst mode only when the all of them are light load condition. Minimum of the additional components are required for the implementation of the proposed method because the load information is obtained from the existing feedback circuit of the post-stage linear regulator. In this paper, the operating principles of the proposed standby-mode circuit are presented with an numerical analysis, and are verified by 25W hardware prototype implementation.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.1
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• pp.70-82
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• 2014

A nano-power CMOS voltage reference is proposed in this paper. Through a combination of switched-capacitor technology with the body effect in MOSFETs, the output voltage is defined as the difference between two gate-source voltages using only a single PMOS transistor operated in the subthreshold region, which has low sensitivity to the temperature and supply voltage. A low output, which breaks the threshold restriction, is produced without any subdivision of the components, and flexible trimming capability can be achieved with a composite transistor, such that the chip area is saved. The chip is implemented in $0.18{\mu}m$ standard CMOS technology. Measurements show that the output voltage is approximately 123.3 mV, the temperature coefficient is $17.6ppm/^{\circ}C$, and the line sensitivity is 0.15 %/V. When the supply voltage is 1 V, the supply current is less than 90 nA at room temperature. The area occupation is approximately $0.03mm^2$.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.85-88
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• 2016

Two output ports of $90^{\circ}$ hybrid-coupler are generally the same output power with $90^{\circ}$ phase difference. But, Two output ports of $90^{\circ}$ hybrid-coupler must be the different output slope characteristic about frequency because of the different electrical length. In $90^{\circ}$ hybrid-coupler being the same power distribution, 3-dB power distribution at two output ports only exists near the center frequency. And, the output power difference between two output ports increases in accordance with the further away from the center frequency. This paper proposes $90^{\circ}$ hybrid-coupler being the similar output slope characteristic of two output ports in wideband to modify the ${\lambda}/4$ transmission line of $35-{\Omega}$ characteristic impedance between input port and output port near input port. The power difference between two output ports of the proposed circuit is below 0.2dB over 20% bandwidth of the center frequency in ADS(advanced Design System).

• Proceedings of the Korean Society for Language and Information Conference
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• 2007.11a
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• pp.375-384
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• 2007

This paper describes a method for automatic acquisition of wide-coverage treebank-based deep linguistic resources for Japanese, as part of a project on treebank-based induction of multilingual resources in the framework of Lexical-Functional Grammar (LFG). We automatically annotate LFG f-structure functional equations (i.e. labelled dependencies) to the Kyoto Text Corpus version 4.0 (KTC4) (Kurohashi and Nagao 1997) and the output of of Kurohashi-Nagao Parser (KNP) (Kurohashi and Nagao 1998), a dependency parser for Japanese. The original KTC4 and KNP provide unlabelled dependencies. Our method also includes zero pronoun identification. The performance of the f-structure annotation algorithm with zero-pronoun identification for KTC4 is evaluated against a manually-corrected Gold Standard of 500 sentences randomly chosen from KTC4 and results in a pred-only dependency f-score of 94.72%. The parsing experiments on KNP output yield a pred-only dependency f-score of 82.08%.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.2
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• pp.159-167
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• 1996

In this paper, a new competitive learning algorithm called dynamic competitive learning (DCL) is presented. DCL is a supervised learning mehtod that dynamically generates output neuraons and nitializes weight vectors from training patterns. It introduces a new parameter called LOG (limit of garde) to decide whether or not an output neuron is created. In other words, if there exist some neurons in the province of LOG that classify the input vector correctly, then DCL adjusts the weight vector for the neuraon which has the minimum grade. Otherwise, it produces a new output neuron using the given input vector. It is largely learning is not limited only to the winner and the output neurons are dynamically generated int he trining process. In addition, the proposed algorithm has a small number of parameters. Which are easy to be determined and applied to the real problems. Experimental results for patterns recognition of remote sensing data and handwritten numeral data indicate the superiority of dCL in comparison to the conventional competitive learning methods.

• Journal of Information Technology Services
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• v.13 no.3
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• pp.165-181
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• 2014

This study proposes the accurate labor inducement coefficient (employment inducement coefficient/hiring inducement coefficient) of Korea software industry by analyzing the inter-industry relation using the modified inter-industry table. To rewrite the inter-industry table of Korea, some previous studies related to the inter-industry analysis were reviewed and the key problems were identified. First, in the current inter-industry table published by the Bank of Korea, the output of software industry includes not only the pure software related output but also the output of non-software section due to the misclassification of the industry. This causes the output to become bigger than the actual output of software industry. Therefore, if the inter-industry table is not modified, the labor inducement coefficient would be overestimated too much. Second, during rewriting the inter-industry table, the output is changing. The inter-industry table is the table in the form of rows and columns, which records the transactions of goods and services among industries which are required to continue the activities of each industry. Accordingly, if only an output of a specific industry is changed, the reliability of the table would be degraded because the table is prepared based on the relations with other industries. This possibly causes the labor inducement coefficient to be over or underestimated. This study tries to correct these problems to get the more accurate labor inducement coefficient of the software industry. First, to get the output of the pure software section only, the data from the Korea Electronics Association (KEA) was used in the inter-industry table. Second, to prevent the difference in the outputs during rewriting the inter-industry table, the difference between the output in the current inter-industry table and the output from KEA data was identified and then it was defined as the non-software section output for the analysis. The followings are the labor inducement coefficient obtained when the output is divided into the pure software section (package software, and IT service) and non-software section. As of 2011, the employment inducement coefficients of pure software section, package software section and IT service of Korea were 8.616, 13.998, and 7.773 respectively while the labor inducement coefficients of pure software section, package software section and IT service of Korea were 7.979, 13.332, and 7.083, respectively.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.10
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• pp.1079-1086
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• 2015

This paper introduces the architecture of OUTPUT module that is suitable using in safety related system having SIL4 and proposes the quantitative target that is required for OUTPUT module. Especially, only output type that is made up Relay output signal and analog signal among various output ways is applied in output module that is a part of safety related system. The FMEA(Failure Modes and Effect Analysis), FTA(Fault Tree Analysis) are used as analysis method. As a result, it proposes to the architecture and failure frequency of the Output module that is used in SIL4 safety related system.

• Journal of Advanced Information Technology and Convergence
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• v.9 no.1
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• pp.25-37
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• 2019

Power-line communication (PLC) has influenced smart grid development. In addition, PLC has also been instrumental in current research on internet-of-things (IoT). Due to the implementation of PLC in smart grid and IoT environments, strides have been made in PLC and its combination with the wireless system to form a hybrid communication system. Also, PLC has evolved from a single-input-single-output (SISO) configuration to multiple-input-multiple-output (MIMO) configuration system, and from a point-to-point communication system to cooperative communication systems. In this work, we extend a MIMO wireless two-way amplify-and-forward (AF) cooperative communication system to a hybrid PLC and wireless (PLC/W) system configuration. We then maximize the weighted sum-rate for the hybrid PLC/W by optimizing the precoders at each node within the hybrid PLC/W system. The sum-rate problem was found to be non-convex, therefore, an iterative algorithm is used to find the optimal precoders that locally maximize the system sum-rate. For our simulation results, we compare our proposed hybrid PLC/W configuration to a PLC only and wireless only configuration at each node. Due to an improvement in system diversity, the hybrid PLC/W configuration outperformed the PLC only and wireless only system configurations in all simulation results presented in this paper.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.3
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• pp.559-564
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• 2010

The GMDH(Group Method of Data Handling) algorithm can be used to predict the complex nonlinear systems. The traditional GMDH algorithm produces the prdicted output of the system model in the output layer through the input layer and the intermediate layers as the prescribed process. The outputs of each layer are produced only by the outputs of the former layer. However, in the traditional GMDH algorithm, though the optimal structure of each layer is derived, the overall structure may not be derived optimally. To overcome this problem, GMDH prediction model which has the overall optimal structure is constructed by feeding back the error between the predicted output and the real output. This can make the prediction more precise. The capability improvement of the proposed algorithm compared to the traditional algorithm is verified through computer simulation.