• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.5
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• pp.685-690
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• 2021

In this paper, we propose a deep learning-based transmit power control scheme to maximize the sum-rates while satisfying the minimum data-rate in downlink non-orthogonal multiple access (NOMA) systems. In downlink NOMA, we consider the co-channel interference that occurs from a base station other than the cell where the user is located, and the user feeds back the signal-to-interference plus noise power ratio (SINR) information instead of channel state information to reduce system feedback overhead. Therefore, the base station controls transmit power using only SINR information. The use of implicit SINR information has the advantage of decreasing the information dimension, but has disadvantage of reducing the data-rate. In this paper, we resolve this problem with deep learning-based training methods and show that the performance of training can be improved if the dimension of deep learning inputs is effectively reduced. Through simulation, we verify that the proposed deep learning-based power control scheme improves the sum-rate while satisfying the minimum data-rate.

• Journal of Korea Society of Waste Management
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• v.35 no.8
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• pp.762-769
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• 2018

This study was carried out to examine the improvement plan by analyzing the characteristics of imported wastes, operation rate, and benefits of energy recovery for incineration facilities with a treatment capacity greater than 50 ton/day. The incineration facility capacity increased by 3,280 tons over 15 years, and the actual incineration rate increased to 2,783 ton/day. The operation rate dropped to 76% in 2010 and then rose again to 81% in 2016. The actual calorific value compared to the design calorific value increased by 33.8% from 94.6% in 2002 to 128.4% in 2016. The recovery efficiency decreased by 29% over 16 years from 110.7% to 81.7% in 2002. Recovery and sales of thermal energy from the incinerator (capacity 200 ton/day) dominated the operation cost, and operating income was generated by energy sales (such as power generation and steam). The treatment capacity increased by 11% to 18% after the recalculation of the incineration capacity and has remained consistently above 90% in most facilities to date. In order to solve the problem of high calorific value waste, wastewater, leachate, and clean water should be mixed and incinerated, and heat recovery should be performed through a water-cooled grate and water cooling wall installation. Twenty-five of the 38 incineration facilities (about 70%) are due for a major repair. After the main repair of the facility, the operation rate is expected to increase and the operating cost is expected to decline due to energy recovery. Inspection and repair should be carried out in a timely manner to increase incineration and heat energy recovery efficiencies.

• International Area Studies Review
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• v.14 no.2
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• pp.79-105
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• 2010

This paper investigates empirically the impact of foreign investors on a firm's dividend and investment decision making in Korean stock market. Empirical results using the sample firms in non-financial firms listed in Korean stock market whose settlement month are December, we find that foreign investors who declared participation in management didn't exert significant impact on dividend increase. In the case of investment, foreign investors exerts significant impact on R&D investments. Using Hausman-Taylor Instrumental Variable method, we controlled endogeneity problem related with foreign ownership and dividend and investment policy. The contribution of this paper is that the purpose of foreign investors whether or not participate in management is the most critical point and the impacts of foreign investors on dividends and investment are different whether they participate in management or not.

• Korean Journal of Metals and Materials
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• v.48 no.1
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• pp.49-56
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• 2010

This study investigated how the surface of Al-12wt.%Si alloy modified by the plasma electrolytic oxidation process (PEO). The PEO process was performed in an electrolyte with sodium hexametaphsphate as a conducting salt, and the effect of ammonium metavanadate on variations in the morphology of electrochemically generated oxide layers on the alloy surface was investigated. It is difficult to form a uniform passive oxide layer on Al alloys with a high Si content due to the differences in the oxidation behavior of the silicon-rich phase and the aluminum-rich phase. The oxide layer covered the entire surface of the Al-12WT.%Si alloy uniformly when ammonium metavanadate was added to the electrolyte. The oxide layer was confirmed as a mixture of $V_2O_3$ and $V_2O_5$ by XPS analysis. In addition, the oxide layer obtained by the PEO process with ammonium metavanadate exhibited a black color. Application of this surface modification method is expected to solve the problem of the lack of uniformity in the coloring of oxide layeres caused by different oxidation behaviors during a surface treatment.

• New Physics: Sae Mulli
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• v.68 no.12
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• pp.1338-1346
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• 2018

The purpose of this study is to analyze the curriculum of a university-affiliated science gifted education center based on the core competencies and to suggest a direction for improving the education at the gifted education center. For this purpose, we set the 12 core competencies as follows: 6 cognitive competencies such as knowledge, creativity, scientific thinking ability, inquiry ability, problem solving ability and fusion ability, and 6 non-cognitive competencies such as task commitment, self-directed learning ability, motivation reinforcement and challenge, communication skills, collaboration ability and leadership. The curricula of the science gifted education centers reflect all the competencies, but some competencies are only potentially included in the contents of the programs. In this study, we present examples of education programs by each competences and suggest additional descriptions for the development of gifted education centers.

• The Southeast Asian review
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• v.23 no.1
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• pp.1-44
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• 2013

This study examined the constitutional engineering of the Philippine democracy in terms of power sharing and accountability, and the effectiveness and stability of the Philippine democracy as a result were assessed. Based on the analysis, the nature of the present Philippine democratic system since 1986 was brought to light. This study argues that the system of power sharing between the President and the congress in the Philippines tends to serve for negotiating political interests among the power elites rather than functioning in a constructive way. And the public accountability system is not functioning as it was designed to do. Due to the defects the Philippine democracy continuously suffers the lack of political effectiveness and stability. Despite of the problem, the reason not to break down the system would be the fact that the system served for the oligarchic power elites to circulate and recreate the political power exclusively. The direction of the Philippine constitutional engineering should be weakening the present traditional elite dominated political system, and strengthening the chances of political participation from the various classes. Some concerned people suggested the constitutional change to parliamentary system in order to strengthening party politics, and federal system to cope with the problems of regional conflicts, but such efforts failed repeatedly due to the conflict of political interests. Considering the present circumstance, it would be advisable to reform political party law and election system in the direction of strengthening political party system, and to expand the scope of local government system in the direction of devolving the centralized political power.

• Journal of Family Relations
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• v.22 no.1
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• pp.23-40
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• 2017

Objectives: The major purpose of the study is to examine structural relation among teenager's perception of parenting attitudes, peer attachment, resilience and meaning in life. In order to achieve purpose of the study, we will develop reliable criterion which can measure variable. Method: We will set up structural relational model from relationship between internal and external variables that can influence teenager's meaning in life and we will examine the relationship between variables through structural equation analysis. we will find structural relationship among parenting attitudes, peer attachment, resilience and meaning in life. Results: We analyzed structural relationship among variables targeting 744 middle school and high school students. Teenager's perception of parenting attitudes have positive influence on peer attachment. This shows that teenager perception of fostering attitude have a positive influence even though teenager percepts parent's foster attitude as overprotective or compassionate. However, if teenager percept fostering attitude as overprotective, teenager perception of parenting attitudes doesn't have influence on resilience. Parent's compassionate attitude not only directly influence resilience but also influence resilience through peer attachment. This validates that individual psychological factor, such as how teenager accept and interpret surrounding environment can influence resilience. Peer attachment relationship not only directly influence resilience but also influence meaning of life through resilience. The resilience has direct effect on meaning in life. Conclusions: When one of education goal is to help teenager to find meaning in life and to reach self-realization, We need to have interest in resilience which is known factor for contributing meaning in life. As previous teenager studies has approached this problem, such as maladjustment, delinquency, and depression, it is significant that this study is examined in positive a psychological perspective which focus on healthy adjustment, such as meaning in life based on teenager's resilience and happiness.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.6
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• pp.99-119
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• 2007

The USB flash drive is common used for portable storage. That is able to store large data and transfer data quickly and carry simply. But when you lose your USB flash drive without any security function in use, all stored data will be exposed. So the new USB flash drive supported security function was invented to compensate for the problem. In this paper, we analyze vulnerability of 6 control access program for secure USB flash drives. And we show that exposed password on communication between secure USB flash drive and PC. Also we show the vulnerability of misapplication for initialization. Further we develop a protection profile for secure USB flash drive based on the common criteria version 3.1. Finally, we examine possible threat of 6 secure USB flash drives and supports of security objectives which derived from protection profile.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.3
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• pp.101-108
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• 2007

We follow the promising recent results of deploying the public key cryptography in sensor networks. Recent results have shown that the public key algorithms are computationally feasible on the typical sensor nodes. However, once the public key cryptography is brought to the sensor network, security services such like key authentication will be critically required. In this paper we investigate the public key authentication problem in the sensor network and provide several authentication protocols. Our protocols are mainly based on the non-solvable overhearing in the wireless environment and a distributed voting mechanism. To show the value of our protocols, we provide an extensive analysis of the used resources and the resulting security level. As well, we compare our work with other existing works. For further benefit of our protocols, we list several additional applications in the sensor network where our protocols provide a sufficient authentication under the constrained resources.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.6A
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• pp.129-137
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• 2008

As the use of the internet increases, the distribution of spam mail has also vastly increased. The email's main use was for the exchange of information, however, currently it is being more frequently used for advertisement and malware distribution. This is a serious problem because it consumes a large amount of the limited internet resources. Furthermore, an extensive amount of computer, network and human resources are consumed to prevent it. As a result much research is being done to prevent and filter spam. Currently, research is being done on readable sentences which do not use proper grammar. This type of spam can not be classified by previous vocabulary analysis or document classification methods. This paper proposes a method to filter spam by using the subject of the mail and N-GRAM for indexing and Bayesian, SVM algorithms for classification.