• International Journal of Highway Engineering
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• v.17 no.5
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• pp.93-103
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• 2015

PURPOSES : The purpose of this study is to present a linear programing optimization model for the design of lane-based lane-uses and signal timings for an isolated intersection. METHODS: For the optimization model, a set of constraints for lane-uses and signal settings are identified to ensure feasibility and safety of traffic flow. Three types of objective functions are introduced for optimizing lane-uses and signal operation, including 1) flow ratio minimization of a dual-ring signal control system, 2) cycle length minimization, and 3) capacity maximization. RESULTS : The three types of model were evaluated in terms of minimizing delay time. From the experimental results, the flow ratio minimization model proved to be more effective in reducing delay time than cycle length minimization and capacity maximization models and provided reasonable cycle lengths located between those of other two models. CONCLUSIONS : It was concluded that the flow ratio minimization objective function is the proper one to implement for lane-uses and signal settings optimization to reduce delay time for signalized intersections.

• Journal of Korean Society of Transportation
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• v.31 no.4
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• pp.3-17
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• 2013

The purpose of this study is to develop a traffic assignment model where the variable of signal intersection delay is taken into account in assigning traffic in large-scale network settings. Indeed, despite the fact that the majority of the increase in travel time or cost involving congested urban network or interrupted flow are accounted for by stop delays or congested delays at signal intersections, the existing traffic assignment models did not reflect this. The traffic assignment model considering intersection delays presented in this study was built based on the existing traffic assignment models, which were added to by the analysis technique for the computation of intersection delay provided in Korea Highway Capacity Manual. We can conclude that a multiple variety of simulation tests prove that this model can be applied to real network settings. Accordingly, this model shows the possibility of utilizing a model considering intersection delay for traffic policy decisions through analysis of effects of changes in traffic facilities on large urban areas.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.9 no.3
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• pp.92-101
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• 2010

Energy efficiency and safe mobility are the two key constituents of the future automobile. The technologies that enable these features are now heavily dependent upon information and communication technology rather than traditional auto-mechanical technology. This paper presents an exploratory project 'Smart&Green Vehicle Project' at Western Michigan University which is to improve the geographical location accuracy of vehicles and to study various applications of making such location data available. Global Positioning System (GPS), Inertial Navigation System (INS), Vehicular Ad-hoc Network (VANET) technology, and data fusion among these technologies are investigated. Testing and evaluation is done on systems which will gather vehicular positioning data during GPS signal loss. Vehicles in urban settings do not acquire accurate positioning data from GPS alone; therefore there is a need for exploration into technology that can assist GPS in urban settings. The goal of this project is to improve the accuracy of positioning data during a loss of GPS signal. Controlled experiments are performed to gather data which aided in assessing the feasibility of these technologies for use in vehicular platforms.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.51 no.6
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• pp.272-277
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• 2002

This paper deals with the vibration deflection shape measurement technique for a sinusoidally excited structure using a continuously scanning laser Doppler vibrometer (CSLV). The CSLV output signal is an amplitude-modulated vibration in which the excitation signal is modulated by the deflection shapes, and thus the deflection shapes of vibration defined along a scan line can be derived by the envelop and the phase information of the CSLV output signal. In this work, a Hilbert transform based approach has been proposed for measurement of deflection shapes. This technique is as simple as the demodulation technique and allows more convenient experimental settings than the Fourier transform approach. The feasibility of the proposed technique is illustrated along with results of experiment.

• International Journal of Highway Engineering
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• v.15 no.6
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• pp.125-133
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• 2013

PURPOSES : The purpose of this study is to propose delay-minimizing operation methodology of a signalized intersection based upon optimization of lane-uses on approaching lanes for an intersection. METHODS : For the optimization model of lane-uses, a set of constraints are set up to ensure feasibility and safety of the lane-uses, traffic flow, and signal settings. Minimization of demand to saturation flow ratio of a dual-ring signal control system is introduced to the objective function for delay minimization and effective signal operation. Using the optimized lane-uses, signal timings are optimized by delay-based model of TRANSYT-7F. RESULTS : It was found that the proposed objective function is great relation with delay time for an intersection. From the experimental results, the method was approved to be effective in reducing delay time. Especially, cases for two left-turn lanes reduced greater delays than those for a left turn lane. It is noticed that the cases for different traffic volume by approach reduced greater delays than those for the same traffic volume by approach. CONCLUSIONS : It was concluded that the objective function is proper for lane-uses optimizing model and the operation method is effective in reducing delay time for signalized intersections.

• International Journal of Internet, Broadcasting and Communication
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• v.11 no.3
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• pp.34-40
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• 2019

In spatial modulation (SM), both the signal symbol and spatial symbol, i.e., the index of the antenna from which signal symbol is transmitted, carry information. To increase the number of bits carried by spatial symbols, more transmit antennas are required. In the generalized SM (GSM), the same signal symbol is transmitted from a combination of antennas, resulting in a reduction in the number of antennas required to achieve a given spectral efficiency. In this paper, we propose a rotated-symbol GSM (RGSM), in which the signal symbol is rotated with an angle corresponding to the position of the antenna index within the combination. This increases the number of spatial symbols by a factor equivalent to the length of the antenna combinations of the GSM. Numerically, SM, GSM and RGSM require 128, 17 and 12 transmit antennas to convey seven bits through the spatial symbols. Simulation results show that RGSM performs relatively close to GSM, and in several system settings, their error performances coincide.

• Journal of Korean Society of Transportation
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• v.10 no.2
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• pp.43-54
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• 1992

전통적인 신호제어모형은 다음의 두가지 결점을 내포하고 있다. 신호현시의 방법을 적정화하는 점이다. Rouphail(1990)은 전통적으로 행해온 신호주기와 녹색시간분할의 적정화에서 더 나아가 현시방법(signal timing)과 좌회전의 문제를 동시적으로 적정화 시킬 수 있는 모형을 제시한 바 있다. 그러나 Rouphail의 모형은 4개 현시에 국한되었고 현시방법(또는 현시의 선택)도 대단히 제약적이었다. 본연구는 이러한 Rouphail의 모형을 실제상황 에 보다 일반성있게 적용할 수 있도록 확장하는 연구이다. 여기서는 현시방법(또는 선택하는 현시으 형태와 수)을 확대시키고 또 연속변수와 이산변수를 동시에 적정화시키는 혼합정수선형계획법을 적용한 컴퓨터 모형을 구성하고 이를 사례 지역에 적용하엿다. 분석결과는 본 모형이 Rouphail 모형과 비교할 때 현시방법의 선택문제에 있어서 뿐만 아니라 좌회전(비보호, 보호 또는 혼합적)현시의 처리에 있어서 훨씬 더 효율적임을 확인하였다.

• Journal of the Korea Safety Management & Science
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• v.9 no.2
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• pp.215-233
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• 2007

Even though the ad hoc Shewhart methods remain controversial due to various mathematical flaws, there is little disagreement among researchers and practitioners when a set of process data has a skewness distribution. In the context and language of process control, the error related to the process data shows that time to signal increases when a control parameter shifts to a skewness direction. In real-world industrial settings, however, quality practitioners often need to consider a skewness distribution. To address this situation, we developed an enhanced design method to utilize advantages of the traditional attribute control chart and to overcome its associated shortcomings. The proposed design method minimizes bias, i.e., an average time to signal for the shift of process from the target value (ATS) curve, as well as it applies a variable sampling interval (VSI) method to an attribute control chart for detecting a process shift efficiently. The results of the factorial experiment obtained by various parameter circumstances show that the VSI c control chart using nearly unbiased ATS design provides the smallest decreasing rate in ATS among other charts for all experimental cases.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.18 no.36
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• pp.253-263
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• 1995

In parameter design, Taguchi's stated objective is to find the setting of product or process design parameters that minimize average quadratic loss-that is, the average squared deviation of the response from its target value. Yet in practice to choose the settings of design parameters he maximizeds a set of measures called signal-to-noise(SN) ratios. In general, Taguchi gave no justification for the use the SN ratios and no explanation of why the two-step procedure that he recommened will minimize average loss. The purpose of this study is comparing and analyzing of performance statistics by Leon et al(PerMIA), Box(Transformation theory), Vining & Myers(Dual Response Systems) and Taguchi(Signal-to-Noise ratios).

• Clinical and Experimental Otorhinolaryngology
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• v.11 no.4
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• pp.267-274
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• 2018

Objectives. Two main digital signal processing technologies inside the modern hearing aid to provide the best conditions for hearing aid users are directionality (DIR) and digital noise reduction (DNR) algorithms. There are various possible settings for these algorithms. The present study evaluates the effects of various DIR and DNR conditions (both separately and in combination) on listening comfort among hearing aid users. Methods. In 18 participants who received hearing aid fitting services from the Rehabilitation School of Shahid Beheshti University of Medical Sciences regularly, we applied acceptable noise level (ANL) as our subjective measure of listening comfort. We evaluated both of these under six different hearing aid conditions: omnidirectional-baseline, omnidirectional-broadband DNR, omnidirectional-multichannel DNR, directional, directional-broadband DNR, and directional-multichannel DNR. Results. The ANL results ranged from -3 dB to 14 dB in all conditions. The results show, among all conditions, both the omnidirectional-baseline condition and the omnidirectional-broadband DNR condition are the worst conditions for listening in noise. The DIR always reduces the amount of noise that patients received during testing. The DNR algorithm does not improve listening in noise significantly when compared with the DIR algorithms. Although both DNR and DIR algorithms yielded a lower ANL, the DIR algorithm was more effective than the DNR. Conclusion. The DIR and DNR technologies provide listening comfort in the presence of noise. Thus, user benefit depends on how the digital signal processing settings inside the hearing aid are adjusted.