• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.23 no.2
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• pp.173-188
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• 2024

With the advancement of autonomous vehicle (AV) technology, autonomous driving on real roads has become feasible. However, there are challenges in achieving complete autonomy due to perceptual blind areas, which occur when the AV's sensory range or capabilities are limited or impaired by surrounding objects or environmental factors. This study aims to analyze AV accident patterns and safety issues of perceptual blind area that may occur in urban areas, with the goal of developing test scenarios for Level 4+ autonomous driving. It utilized AV accident data from the California Department of Motor Vehicles (DMV) to compare accident patterns and characteristics between AVs and conventional vehicles based on activation status of autonomous mode. It also categorized AV disengagement data to identify types and real-world cases of disengagements caused by perceptual blind areas. The analysis revealed that AVs exhibit different accident types due to their safe driving maneuvers, and three types of perceptual blind area scenarios were identified. The findings of this study serve as crucial foundational data for developing Level 4+ autonomous driving test scenarios, enabling the design of efficient strategies to mitigate perceptual blind areas in various scenarios. This, in turn, is expected to contribute to the effective evaluation and enhancement of AV driving safety on real roads.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.1
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• pp.31-40
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• 1992

This paper presents an automatic feature recognition system for recognizing and extracting feature information needed for the process planning input from a 3D CAD system. A given part is modeled by using the AutoCAD and feature information is automatically extracted from the AutoCAD database. The type of parts considered in this study is prismatic parts composed of faces perpendicular to the X, Y, Z axes and the types of features recognized by the proposed system are through steps, blind steps, through slots, blind slots, and pockets. Features are recognized by using the concept of convex points and concave points. Case studies are implemented to evaluate feasibilities of the function of the proposed system. The developed system is programmed by using Turbo Pascal on the IBM PC/AT on which the AutoCAD and the proposed system are implemented.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.6
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• pp.124-130
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• 2010

Current traffic guidance system offers the information of traffic light using a speaker to everybody including the blinds without object certification. Therefore, the current system gives stress by noisy sound to normal person. It is difficult for the blind to hear informations such as location, current traffic sign light status, and weather information, because of the vehicle noise and surroundings noise. If the blind or sight disabled person who has the RFID tag or has a white stick with RFID tag approaches to street crossing, RFID reader recognizes the tag and it serves necessary information through speaker or bluetooth. And also it is possible for the blind to use less expensive one with RFID tag than the white stick with RFID Reader.

• Journal of the Korean Solar Energy Society
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• v.32 no.2
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• pp.74-86
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• 2012

For the improvement of environmental comfort in the buildings with the blind control, the objective of this study is to prevent the direct glare caused by the daylight inlet. During the process of solar profile prediction, time are significant factors that may cause error and glare during the blind control. This research proposes and evaluates the correction and control method to minimize prediction error. For the local areas with different longitude and local standard meridian, error occurred in the process of the time conversion from local standard time to apparent solar time. In order to correct error in time conversion, apparent solar time should be recalculated after adjusting the day of year and the equation of time. To solve the problems by the potential time errors, control method is suggested to divide the control sections using the calibrated fitting-curve and this method is verified through simulations. The proposed correction and control method, which considered potential time errors by loop lop leap years, could solve the problems about direct glare caused by daylight inlet on the work-plane according to the prediction errors of solar profile. And also these methods could maximize daylight inlet and solar heat gain, because the blocked area on windows could be minimized.

• ETRI Journal
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• v.42 no.3
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• pp.324-332
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• 2020

In this paper, a blind symbol timing offset (STO) estimation method is proposed for offset quadrature phase-shift keying (OQPSK) modulated signals, which also works for other linearly modulated signals (LMS) such as binary-PSK, QPSK, 𝜋/4-QPSK, and minimum-shift keying. There are various methods available for blind STO estimation of LMS; however, none work in the case of OQPSK modulated signals. The popular cyclic correlation method fails to estimate STO for OQPSK signals, as the offset present between the in-phase (I) and quadrature (Q) components causes the cyclic peak to disappear at the symbol rate frequency. In the proposed method, a set of close and approximate offsets is used to compensate the offset between the I and Q components of the received OQPSK signal. The STO in the time domain is represented as a phase in the cyclic frequency domain. The STO is therefore calculated by obtaining the phase of the cyclic peak at the symbol rate frequency. The method is validated through extensive theoretical study, simulation, and testbed implementation. The proposed estimation method exhibits robust performance in the presence of unknown carrier phase offset and frequency offset.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.559-562
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• 1999

In this paper, we developed on internet based assembly information display system for the blind. The system is consist of hardware and software. The hardware is consist of a voice synthesis device and a tactile display for character information, and the software is consist of internet web browser for the blind and braille program. The tactile-device system consists of a control unit, pin array, pin generator, serial port, and a power supply. The pin exerted by a electromagnetic method, solenoid. The internet web browser separates the character and image from internet web page, and character information in the web page is converted to braille and fed to sound system. Also the image in the web page can be printed developed tactile display. As the results of experiment, the blind could access the internet web site by using this system and understand various internet information.

• KIEAE Journal
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• v.7 no.1
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• pp.23-31
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• 2007

This study aims to evaluate the illuminance performance of sloped light guide with automated venetian blind systems. For the purpose, a mock-up model was constructed as a prototype of Korean office building with $12.0m{\times}7.3m{\times}3.7m$ ($w{\times}d{\times}h$) and south facing side-window mounted between the clerestory window($2.0m^2$) and the view window($5.6m^2$). The light guide of 1.28m deepth and $29^{\circ}$ tilted angle, is covered with 0.6mm galvanized steel sheet and 97% reflective film. To protect the room from low solar angle, a blind systems, 0.15m deepth and $30^{\circ}$ automated slat angle was installed. To assess illuminance performance, the totally 37 measuring points for illuminance were monitored. For the detailed analysis, photometric sensors were installed at work-plane (8 points), wall (7 points), ceiling (3points), and exterior horizontal illuminance (1 point) respectively. The performance was measured under clear sky and is monitored by Agilent data logger, photometric sensor Li-cor and the Radiant Imaging ProMetric 1400. Comparisons of light factor and uniformity are discussed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.6
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• pp.515-520
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• 2012

A daylighting system includes three parts; light collector, light transformer and light distributor. A DBLP(Double blind light pipe) daylighting system consists of a double blind light collector, a mirror duct type light transformer and a prism film light pipe distributor. The double blinds for a light collection are used to track the sun's altitude and azimuth movements throughout the day. Behind both sets of blinds is the light transformer, which is based on a rectangular cone shaped light duct. The light transformer was designed to efficiently deliver the light into the light pipe within a 30 degree radial spread for the efficient light into the distributor. In this study, DBLP system efficiency was simulated, evaluated and optimized by Tracepro as a popular ray trace light design simulation program. The results indicated that DBLP system efficiency evaluated a maximum 22.4% in case of Spring/Fall season solar noon time. While the overall average system efficiency in the morning and afternoon is evaluated about 10%.

• Korean Journal of Biological Psychiatry
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• v.4 no.1
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• pp.127-131
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• 1997

Objective : To evaluate the clinical efficacy of adjuvant sertraline treatment in chronic schizophrenic patients, we carried out a double-blind, placebo controlled study. Method : Thirty six inpatients who fulfilled DSM-III-R criteria for chronic schizophrenia were randomly assigned to sertraline and placebo groups in a double-blinded fashion. A history of at least 2 years of illness and at least six months of hospitalization were prerequisities for inclusion in the study. Patients were received sertraline 50mg or placebo for 8 weeks in addition to their routine haloperidol regimen. Positive and Negative Syndrome Scale (PANSS), Clinical Global Impression(CGI), Simpson-Angus Scale(S-A) were evaluated at 5 points ; baseline, 2, 4, 6, and 8 weeks of treatment. Results : The groups were controlled for age, gender, and length of illness. There were no significant differences in three PANSS factros(positive, negative, general), CGI, and S-A scale scores at any between sertaline and placebo treatment. Conclusion : This placebo controlled study showed no significant effects of sertraline on negative and positive symptoms in chronic schizophrenic patients.

• Journal of Korea Multimedia Society
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• v.9 no.12
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• pp.1689-1699
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• 2006

A nonlinear channel blind equalizer by using a hybrid genetic algorithm, which merges a genetic algorithm with simulated annealing, and a RBF network is presented. In this study, a hybrid genetic algorithm is used to estimate the output states of a nonlinear channel, based on the Bayesian likelihood fitness function, instead of the channel parameters. From these estimated output states, the desired channel states of the nonlinear channel are derived and placed at the center of a RBF equalizer to reconstruct transmitted symbols. In the simulations, binary signals are generated at random with Gaussian noise. The performance of the proposed method is compared with those of a conventional genetic algorithm(GA) and a simplex GA, and the relatively high accuracy and fast convergence of the method are achieved.