• The Journal of the Acoustical Society of Korea
• /
• v.30 no.3
• /
• pp.115-122
• /
• 2011

In this paper, we present a method to estimate an accurate real-time sound source direction based on time delay of arrival by using generalized cross correlation with four cross-type microphones. In general, existing systems have two disadvantages such as system embedding limitation due to the necessity of data acquisition for signal processing from microphone input, and real-time processing difficulty because of the increased number of channels for sound direction estimation using DSP processors. To cope with these disadvantages, the system considered in this paper proposes hardware design for enhanced real-time processing using microphone array signal processing. An accurate direction estimation and its design time reduction is achieved by means of an efficient hardware design using spatial segmentation methods and verification techniques. Finally we develop a system which can be used for embedded systems using a sound codec and an FPGA chip. According to experimental results, the system gives much faster real-time processing time compared with either PC-based systems or the case with DSP processors.

• Transactions on Electrical and Electronic Materials
• /
• v.16 no.6
• /
• pp.293-302
• /
• 2015

Degraded data stability, weaker write ability, and increased leakage power consumption are the primary concerns in scaled static random-access memory (SRAM) circuits. Two new SRAM cells are proposed in this paper for achieving enhanced read data stability and lower leakage power consumption in memory circuits. The bitline access transistors are asymmetrically gate-underlapped in the proposed SRAM cells. The strengths of the asymmetric bitline access transistors are weakened during read operations and enhanced during write operations, as the direction of current flow is reversed. With the proposed hybrid asymmetric SRAM cells, the read data stability is enhanced by up to 71.6% and leakage power consumption is suppressed up to 15.5%, while displaying similar write voltage margin and maintaining identical silicon area as compared to the conventional memory cells in a 15 nm FinFET technology.

• Current Optics and Photonics
• /
• v.3 no.4
• /
• pp.292-297
• /
• 2019

We propose a ring resonator-based orbital angular momentum carrying vortex beam generator design with high vertical directional emission efficiency. By adopting a vertically asymmetric grating structure in the ring resonator, optimized for enhanced vertical emission, an emission efficiency in one direction reaches as high as 78%, exceeding the 50% theoretical limit of previously designed vertically symmetric grating-assisted ring resonator-based structures.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.6
• /
• pp.627-635
• /
• 2017

Modern warfare is gradually changing into a network war, and information electronic warfare is also progressing. In modern war, electronic warfare is all military activity concerned with electromagnetic field use, such as signal collecting, communication monitoring, information analysis, and electronic attack. The one key function of signal collecting for enemy signal analysis, direction finding, collects the signal radiated from enemy area and then calculates the enemy direction. This paper examined the Watson-Watt algorithm for an amplitude direction finding system and CVDF algorithm for phase direction finding system and analyzed the difference in the direction finding accuracy between in the clean electromagnetic field environment and in the real operating field environment of electronic warfare system. In the real field, the direction finding accuracy was affected by the reflected field from the surrounding obstacles. Therefore, this paper proposesan enhanced direction finding process for reducing the effect. The result of direction finding by applying the proposed process was enhanced above $1.24^{\circ}$ compared to the result for the existing process.

• Journal of The Korean Astronomical Society
• /
• v.29 no.spc1
• /
• pp.57-58
• /
• 1996

There is an excess gamma flux from the general direction of the Galactic North Pole compared with that from the south when allowance is made for the contribution from CR interactions with the HI gas (Osborne et al., 1994). The extent to which it is in accord with the predictions of Wdowczyk and Wolfendale (1990 a,b) for gamma rays secondary to very high energy CR escaping from the VIRGO cluster is examined and it is claimed that the observations may well be of the order of those expected.

• Computers and Concrete
• /
• v.15 no.1
• /
• pp.21-35
• /
• 2015

The objective of this study is to examine the effect of carbon fiber reinforced polymer (CFRP) on the shear strengths of deep beams with web openings. A total of 18 high-strength concrete deep beams with web openings were tested. Twelve were externally wrapped with four layers of CFRP, six of them strengthened in the horizontal direction and the others in the vertical direction. The parameters of the configuration of CFRP, the sizes of the openings and the locations of the openings were covered in this study. The test results indicates the shear strengths of deep beams with openings sized $60{\times}40mm$ were about 16% higher than that with openings sized $68{\times}68mm$. For deep beams with openings sized $60{\times}40mm$, the lower the locations of openings the higher the shear strengths were. The test results also indicate the shear strengths of deep beams with web openings strengthened by CFRP wrapped in the vertical direction can be enhanced by about 10%. However, the shear strengths of deep beams with web openings strengthened by CFRP wrapped in the horizontal direction can only be enhanced by about 6%. The shear strengths of deep beam, with different size and location of web openings and strengthened by different configuration of CFRP can be reasonably predicted by the empirical formulas of Kong and Sharp.

• The Journal of the Korea Contents Association
• /
• v.14 no.9
• /
• pp.45-53
• /
• 2014

In this study, we analyzed the next generation ITS (C-ITS) technology trends, focusing on the national and international C-ITS projects. Based on the promotion practices of developed countries, we pointed out the lack of linkages with the existing ITS infrastructure. As a way to overcome this problem, we proposed the three-direction to enable the existing ITS infrastructure corresponding to the C-ITS. First one is developing a technique to improve the performance of the existing ITS infrastructure and automate the performance management (Performance-enhanced ITS). Second, developing active sensors or fusion sensor which along with V2X communication technology implement of an active safety driving support system (Safety-enhanced ITS). Third, we need to develop a technology that generate the new advanced traffic data by integrating the collected data from existing ITS infrastructure and nomadic device (Cloud-ITS). By improving the function of the existing ITS infrastructure for adaptation to the new V2X communication environment, we enhanced the efficiency of maintenance performance and would maximize the benefit of the introduction of C-ITS.

• Journal of Korea Game Society
• /
• v.11 no.1
• /
• pp.37-46
• /
• 2011

Due to the advent of high performance feature-phone and smart-phone, the scale of mobile games and the member of developers are increased rapidly. The production process of mobile games is changing to meet these needs. Tools for efficient program development are produced worldwide, but tool's research for the event direction is inadequate. In the event direction, the game designers play more important roles than programmers. In this paper, we develop the mobile game event direction tool for game designers. And we make the events of the released mobile games to test the efficiency and usefulness of tool that we developed. The result shows that the performance is enhanced about 15% in development period.

• Journal of Korean Association for Spatial Structures
• /
• v.6 no.3 s.21
• /
• pp.43-50
• /
• 2006

This paper is concerned with the natural periods of ambient vibration and eigenvalue analysis. Ambient vibration tests were conducted to four bearing-wall reinforced concrete buildings ranging from twelve to nineteen stories. The performance of modeling in eigenvalue analysis was investigated using consideration of rigidity out of the plane in the slab and the non-structural bearing wall. Measured natural period was also compared with the value by the KBC2005. Natural period of the short direction in eigenvalue analysis is well fitted with the measured one. In the other hand, Natural period of the long direction in eigenvalue analysis is slightly more overestimated than the measured one. Natural period of the long direction in eigenvalue analysis was found to be enhanced by considering the effect of the stiffness out of the plane of the slab and non-structural wall in the structural modeling.

• Proceedings of the KIEE Conference
• /
• 2005.10b
• /
• pp.180-182
• /
• 2005

Fingerprint-based identification is known to be used for a very long time. Owing to their uniqueness and immutability, fingerprints are today the most widely used biometric features. Therefore, recognition using fingerprints is one of the safest methods as a way of personal identification. But fingerprint identification system has a critical weakness. Since the fingerprint identification time dramatically increase when we compare the unknown fingerprint's minutiae with fingerprint database's minutiae. In this paper, a ridge orientation extraction method using Index table is proposed to solve the problem. The goal of fast direction image extraction is to reduce the identification time and to improve the clarity of ridge and valley structures of input fingerprint image.