• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.9 no.3
• /
• pp.1057-1073
• /
• 2015

In this paper, we consider cooperative D2D communications in cellular networks. More precisely, a cellular user leases part of its spectrum to facilitate the D2D communication with a goal of improving the energy efficiency of a D2D pair. However the D2D pair is untrusted to the cellular user, such resource sharing may result in the information of this cellular user unsecured. In order to motivate the cellular user's generosity, this D2D pair needs to help the cellular user maintain a target secrecy rate. To address this issue, we formulate a joint spectrum and power allocation problem to maximize the energy efficiency of the D2D communication while guaranteeing the physical layer security of the cellular user. Then, a theorem is proved to indicate the best resource allocation strategy, and accordingly, an algorithm is proposed to find the best solution to this resource allocation problem. Numerical results are finally presented to verify the validity and effectiveness of the proposed algorithm.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2008.10a
• /
• pp.594-597
• /
• 2008

This presentation introduces a simple strategy for producing 2D photonic crystal layers (PCL) with different structures. In an attempt to improve extraction efficiency from the thin film phosphors (TFPs), this study have examined the effects of the structural variables of the 2D PCLs on the light extraction efficiency of TFPs.

• Journal of Technology Innovation
• /
• v.27 no.3
• /
• pp.1-26
• /
• 2019

The Korean economy has undergone growth based on manufacturing end products. The Korean government aims to advance industry by strengthening the materials and components industry, which is attracting more attention in terms of maintaining the competitiveness of existing key industries, and fostering new industries required in the era of the Fourth Industrial Revolution. Despite this importance, there is insufficient related research on the efficient R&D of the materials and components industry. This study analyzed the R&D efficiency. In addition, exploratory research was conducted on the impact of corporate size and type of cooperation on R&D efficiency. Output variables were set to reflect economic performance and the empirical analysis revealed that overall R&D efficiency is low. Small firms were found to perform better than large firms in terms of firm-size, and the efficiency of business-university-research cooperation is worse than other types of cooperation. This study is exploratory research considering the materials and components industry, and the results provide implications for research institutions and regarding types of cooperation. This is expected to help develop polices for qualitative growth and R&D strategies for investment and allocation.

• IE interfaces
• /
• v.24 no.4
• /
• pp.314-322
• /
• 2011

This study analyzes a relationship between Data Envelopment Analysis(DEA) efficiency scores and a normalization index in order to examine the validity of DEA models. A normalization index concerned in this study is 'sales per R&D project fund' which is regarded as a crucial R&D project performance evaluation index in practice. For this correlation analysis, three distinct DEA models are selected such as DEA basic model, DEA/AR-I revised model(i.e. DEA basic model with Acceptance Region Type I constraints) and Super-Efficiency(SE) model. Especially, SE model is adopted where efficient R&D projects(i.e. Decision Making Units, DMU's) with DEA efficiency score of unity from DEA basic model can be further differentiated in ranks. Considering the non-normality and outliers, two rank correlation coefficients such as Spearman's ${\rho}_s$ and Kendall's ${\tau}_B$ are investigated in addition to Pearson's ${\gamma}$. With an up-to-date empirical massive dataset of n = 482 R&D projects associated with R&D Loan Program of Korea Information Communication Promotion Fund in the year of 2011, statistically significant (+) correlations are verified between the normalization index and every model's DEA efficiency scores with all three correlation coefficients. Especially, the congruence verified in this empirical analysis can be a useful reference for enhancing the practitioner's acceptability onto DEA efficiency scores as a real-world R&D project performance evaluation index.

• Journal of Korea Technology Innovation Society
• /
• v.13 no.1
• /
• pp.184-203
• /
• 2010

Based on the figure of Program's result, the measurement of National R&D Program efficiency cannot have reflected its characteristic. This study explores the way to integrate evaluators' recognition into program efficiency as a means of embodying its characteristic. As a way of integrating their recognition with evaluating efficiency, two methods are applied. One is AHP as for evaluators recognition and the other is DEA as for measuring efficiency. This study tries to show the effect of evaluators on program efficiency and compares the result with one which did not include their recognition. The study also implies that the recognition of evaluators should be considered when the program efficiency is measured. Furthermore, this study suggests that the participation and role of evaluators should be expanded into evaluation of program efficiency.

• Journal of the Korea Safety Management & Science
• /
• v.16 no.3
• /
• pp.421-432
• /
• 2014

This study is intended to analyze the relation between G. D. Weisman's Way finding 4 elements the accessibility and efficiency of consumers as to eternal area for Seoul historical museum. The findings are summarized as the following three aspects. First, G. D. Weisman's Way finding element introduced in this study had a significant impact on visitor satisfaction.. It leads to the following conclusion: The higher the impact is, the greater accessaccessibility and efficiency are. Second, among 4 elements, the factor that had the biggest impact on the accessibility was 'visual-perceptual accessibility'. Thus, 'visual-perceptual accessibility' should be considered first to boost the accessibility to consumers. Third, among 4 elements, the factor that had the biggest impact on the efficiency was 'sign system'. Thus, 'sign system' should be considered first to boost the efficiency to consumers.

• Proceedings of the IEEK Conference
• /
• 2006.06a
• /
• pp.575-576
• /
• 2006

It was analyzed qualitatively the light extraction in GaN-on-sapphire LEDs based on a simple model. The light extraction efficiency in the LEDs is simulated numerically by using ray tracing method. In the present study, the extraction efficiency was simulated on three different types of LEDs, which a have a different pattered sapphire substrate. And, the role of the patterned sapphire substrate are analyzed and discussed. Based on the analysis, the improvements of extraction efficiency in the LED structures were discussed and these analyses are helpful in the design of high brightness GaN LEDs.

• IE interfaces
• /
• v.19 no.4
• /
• pp.281-290
• /
• 2006

The main objective of this study is to analyze the structure of efficiency of R&D input variables and the attributes of patent information as output of R&D activities in the major manufacturing industries (electric & electronics, machinery, chemical, textile) from the mid-1970s to the late-1990s by the development of "mapping technique". To attain this objective we first have examined the attribute of time-lag which depends on the absolute, and the cumulative values between input and output. And on the basis of this result, we have made an analysis on the impact to extract the main variables affecting patent by industries. Moreover, according to time trend of the impact variables, we have analyzed the structure of R&D efficiency, and of technological progress which will be changed with time by patent information. It has been aimed at constructing technological progress patterns in the Korea industry.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.9
• /
• pp.9-16
• /
• 2020

Wireless charging has been considered an essential part of recent mobile devices. Moreover, various wireless charging systems have emerged through many studies. Among the systems, in the 2D flat coil system, the transmitter coil and receiver coil are arranged horizontally as close as possible to improve the charging efficiency. Nowadays, the 3D coil system has been proposed by adding some slope to flat 2D coils to reduce the volume. On the other hand, the 3D coil system has a lower charging efficiency than the 2D system that decreases rapidly with increasing distance. This paper proposes a new system that improves the low efficiency and charging freedom, which are the drawbacks of the existing 3D systems. The proposed system was designed in three-dimensions, and another transmitter coil was added to the transmitter coil to improve the transmission efficiency and flexibility. The measurement showed that the charging efficiency of the proposed system was 40.10% when the distance between coils was 8 mm, which is 20.5 % improvement over the existing one. The proposed method can be applied when new wireless charging systems are designed and improve charging efficiency can be improved.

• Journal of Korea Multimedia Society
• /
• v.19 no.7
• /
• pp.1208-1215
• /
• 2016

This study suggests efficient production of game with spine tool that is 2D game tool. For this, the researcher studies process and efficiency of game development by focusing on production of a game "Shooting Monster" Version 1 in service of Google Store at present. Production tools in a contents field are sharply changed. In addition, these tools are automatized into new version and efficient product. These tools help manufacturers in increasing quality of contents and time efficiency. Therefore, the researcher examines understanding of development process of existing 2D game and problems in development stage of graphic character, and analyzes production stage of character animation using spine tool, so suggests effective process of production in terms of production. The purpose of this study is to suggest the direction about graphic efficiency of tool by accessing production process to train working-level talented people in 2D mobile game field.