• Title/Summary/Keyword: Urban noise

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Early warning of hazard for pipelines by acoustic recognition using principal component analysis and one-class support vector machines

  • Wan, Chunfeng;Mita, Akira
    • Smart Structures and Systems
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    • v.6 no.4
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    • pp.405-421
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    • 2010
  • This paper proposes a method for early warning of hazard for pipelines. Many pipelines transport dangerous contents so that any damage incurred might lead to catastrophic consequences. However, most of these damages are usually a result of surrounding third-party activities, mainly the constructions. In order to prevent accidents and disasters, detection of potential hazards from third-party activities is indispensable. This paper focuses on recognizing the running of construction machines because they indicate the activity of the constructions. Acoustic information is applied for the recognition and a novel pipeline monitoring approach is proposed. Principal Component Analysis (PCA) is applied. The obtained Eigenvalues are regarded as the special signature and thus used for building feature vectors. One-class Support Vector Machine (SVM) is used for the classifier. The denoising ability of PCA can make it robust to noise interference, while the powerful classifying ability of SVM can provide good recognition results. Some related issues such as standardization are also studied and discussed. On-site experiments are conducted and results prove the effectiveness of the proposed early warning method. Thus the possible hazards can be prevented and the integrity of pipelines can be ensured.

Experiment on the Effective Helix Area to Determine the Bearing Capacity of Helical Steel Piles (나선형 강관파일의 날개 유효면적 산정을 위한 지지력 실험)

  • Lee, Min-Joo;Kim, Kyoung-Min;Rhim, Hong-Chul;Seo, Gum-Bae
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2010.05a
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    • pp.25-27
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    • 2010
  • Helical steel piles are being widely used in foundation for the buildings in urban areas because of their high compressive and tensile capacities. Helical steel piles have many advantages; ease installation, a vibration-free and low level of noise process, and so on. However, the most researches are about the capacity of helical steel piles under uplift condition. Therefore, this paper focuses on the capacity under compressive loading according to the soil condition. The bearing capacity of helical steel piles varies with the diameter of the helix and shaft and the bearing area of helical steel piles is not always identical with the sum of helix and shaft area due to the difference of each bearing mechanism. Therefore, the experiment with the parameters of the ratio of helix and shaft diameter and soil condition will be carried out to survey the effective helix area under a given soil condition for the bearing capacity of helical steel piles.

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The Simulation and Experimental Study on the Bridge Response of AGT Bridge - Vehicle interaction System (AGT 시스템 교량-차량 상호작용에 의한 교량응답 시뮬레이션 및 실험)

  • Na, Sang-Ju;Kim, Ki-Bong;Song, Jae-Pil;Kim, Hyun-Ho
    • Proceedings of the KSR Conference
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    • 2007.11a
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    • pp.395-400
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    • 2007
  • LRT(Light Railway Train), which is a intermediate system of train and bus, is arose for the solution of subway construction cost and the transportation capacity of bus. LRT was introduced in 1980's. About 30 local governments are plan to introduce LRT or constructing LRT, at present. AGT(Automated Guide-way Transit) system, which is a kind of LRT, is operated without driver. Rubber wheeled AGT system can reduce the noise and vibration compare to steel wheeled AGT, so it is estimated as ideal transportation system for urban area. And live loads at bridge are classified as the static load of vehicle and the dynamic wheel contact load which is occurred from the interaction of bridge and vehicle vibration, and the surface roughness. In the case of AGT system, the dynamic increment factor of bridge is greater than the normal train bridge and roadway bridge, because, the weight of AGT vehicle is more light that the train of truck. The exact method for dynamic increment factor is experiment. But this method is needed much money and time, moreover, this method cannot be adopted in design. Therefore, a simulation program for the interaction of AGT bridge, vehicle and surface roughness was developed, in this study. And the program was verified by experiment. As a result, the accuracy of the simulation program can be verified.

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A Microscopic Analysis on the Fundamental Diagram and Driver Behavior (교통기본도와 운전자 행태에 대한 미시적 분석)

  • Kim, Taewan
    • International Journal of Highway Engineering
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    • v.14 no.6
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    • pp.183-190
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    • 2012
  • PURPOSES : The fundamental diagram provides basic information necessary in the analysis of traffic flow and highway operation. When traffic flow is congested, the density-flow points in the fundamental diagram are widely scattered and move in a stochastic manner. This paper investigates the pattern of density-flow point transitions and identifies car-following behaviors underlying the density-flow transitions. METHODS : From a microscopic analysis of 722 fundamental diagrams of NGSIM data, a total of 20 transition patterns of fundamental diagrams are identified. Prominent features of the transition patterns are explained by the behavior of the leader and follower. RESULTS : It is found out that the average speed and the speed difference between the leader and the follower critically determine the density-flow transition pattern. The density-flow path is very sensitive to the values of vehicle speed and spacing especially at low speed and high density such that most fluctuations in the fundamental diagram in the congested regime is due to the noise of speed and spacing variations. CONCLUSIONS : The result of this study suggests that the average speed, the speed difference between the leader and the follower, and the random variations of speed and spacing are dominant factors that explain the transition patterns of a fundamental diagram.

Characteristic of Three-Phase Voltage Type Soft-Switching Inverter using the Novel Active Auxiliary Resonant DC Link Snubber (새로운 액티브 보조 공진 DC 링크 스너버를 이용한 3상 전압형 소프트 스위칭 인버터의 특성)

  • Sung, Chi-Ho;Heo, Young-Hwan;Mun, Sang-Pil;Park, Han-Seok
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.65 no.2
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    • pp.114-121
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    • 2016
  • This paper is Instant space vector PWM(Pulse Width Modulation)power conversion devices in switching power semiconductors from my generation to losses and switching when the voltage surge and current surge of electronic noise(EMI: Electro Magnetic Interference / RFI: Radio Frequency Interference)to effectively minimize the power soft-switching power conversion circuit topologies of auxiliary resonant DC tank for the purpose of high performance realization of the electric power conversion system by the high-speed switching of a semiconductor device(AQRDCT simultaneously : an active auxiliary resonance using auxiliary Quasi-resonant DC tank)DC link snubber switch has adopted a three-phase voltage inverter. AQRDCL proposed in this paper can reduce the effective and current peak stress of the power semiconductors of the auxiliary resonant snubber circuit compared to the conventional active-resonant DC link snubber, it is not necessary to install the clamp switch of the auxiliary resonant DC link, DC the peak current and power loss of the bus line can be reduced.

Vision based Traffic Light Detection and Recognition Methods for Daytime LED Traffic Light (비전 기반 주간 LED 교통 신호등 인식 및 신호등 패턴 판단에 관한 연구)

  • Kim, Hyun-Koo;Park, Ju H.;Jung, Ho-Youl
    • IEMEK Journal of Embedded Systems and Applications
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    • v.9 no.3
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    • pp.145-150
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    • 2014
  • This paper presents an effective vision based method for LED traffic light detection at the daytime. First, the proposed method calculates horizontal coordinates to set region of interest (ROI) on input sequence images. Second, the proposed uses color segmentation method to extract region of green and red traffic light. Next, to classify traffic light and another noise, shape filter and haar-like feature value are used. Finally, temporal delay filter with weight is applied to remove blinking effect of LED traffic light, and state and weight of traffic light detection are used to classify types of traffic light. For simulations, the proposed method is implemented through Intel Core CPU with 2.80 GHz and 4 GB RAM, and tested on the urban and rural road video. Average detection rate of traffic light is 94.50 % and average recognition rate of traffic type is 90.24 %. Average computing time of the proposed method is 11 ms.

Design and Construction Problems of Semi-Shield Method (SEMI-SHIELD 공법의 설계 및 시공상 문제점)

  • Kim, Jong-In;Jung, Sung-Nam;Park, Yeong-Geon
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.09a
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    • pp.1275-1282
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    • 2009
  • The tunnel excavations are used for construction of common utility tunnel, electric tunnel, communication line tunnel, water supply and public sewerage pile line in urban area. The trench cut methods were mainly used in the past, but now, tunneling method is more being used. The tunnel excavation method like as NATM, Messer-Shield, Semi-Shield Methods are being applied to small section tunnel in Korea. The actual construction results of seme-shield method are increasing due to simplified construction process and reduced noise and vibration. And also this method is being used frequently in waterway tunnel and construction of prevention flooding recently. The seme-shield method design guideline is absence except for electric line tunnel construction in Korea, because of the semi-shield method was developed in Europe and Japan. In the prescriptive design, engineer's subjects are tending to intervene, because of absence of standard and specification for details. Therefore, Design and Construction Problems of Semi-Shield Method were described and construction trouble was introduced for exam. These problem and construction troubles have to be examined thoroughly in advance.

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Why Healthy Workplaces Matter

  • Best, Robert S.
    • International Journal of High-Rise Buildings
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    • v.6 no.4
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    • pp.297-300
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    • 2017
  • Employers are realizing that workplaces have an immense impact on productivity. And, because people typically represent about 90% of a company's costs, even a slight improvement in productivity hits the bottom-line in a very big way. The focus is shifting away from saving money by reducing space needs or cutting energy requirements, and moving toward making the workplace friendlier and healthier. What is a healthy workplace, exactly? The answer should be clear by now. Mountains of research have expounded on this very topic, and then news outlets cover the latest discoveres ad infinitum. The problem is, research is rather dense, while the news isn't comprehensive. Office managers trying to improve workplace wellness want neither a 55-page report nor a half dozen articles to convince their landlord that their space can do better. Recognizing this gap, Harvard researchers have released a concise-yet-complete list of healthy building features. Here, we're sharing these nine features with a few insights of our own on the value of being healthy and productive. Find out: ${\bullet}$ What makes a healthy building and why is it so important ${\bullet}$ How to improve the health of your own office ${\bullet}$ What happens for your people and your bottom line when you make health a priority.

Enhancement of Forecasting Accuracy in Time-Series Data, Basedon Wavelet Transformation and Neural Network Training (Wavelet 변환과 신경망을 이용한 시계열 데이터 예측력의 향상)

  • 신승원;최종욱;노정현
    • Journal of Intelligence and Information Systems
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    • v.4 no.2
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    • pp.23-34
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    • 1998
  • Travel time forecasting, especially public bus travel time forecasting in urban areas, is a difficult and complex problem which requires a prohibitively large computation time and years of experience. As the network of target area grows with addition of streets and lanes, computational burden of the forecasting systems exponentially increases. Even though the travel time between two neighboring intersections is known a priori, it is still difficult, if not impossible, to compute the travel time between every two intersections. For the reason, previous approaches frequently have oversimplified the transportation network to show feasibilities of the problem solving algorithms. In this paper, forecasting of the travel time between every two intersections is attempted based on travel time data between two neighboring intersections. The time stamps data of public buses which recorded arrival time at predetermined bus stops was extensively collected and forecast. At first, the time stamp data was categorized to eliminate white noise, uncontrollable in forecasting, based on wavelet conversion. Then, the radial basis neural networks was applied to remaining data, which showed relatively accurate results. The success of the attempt was confirmed by the drastically reduced relative error when the nodes between the target intersections increases. In general, as the number of the nodes between target intersections increases, the relative error shows the tendency of sharp increase. The experimental results of the novel approaches, based on wavelet conversion and neural network teaming mechanism, showed the forecasting methodology is very promising.

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Traffic Analysis of a Cognitive Radio Network Based on the Concept of Medium Access Probability

  • Khan, Risala T.;Islam, Md. Imdadul;Amin, M.R.
    • Journal of Information Processing Systems
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    • v.10 no.4
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    • pp.602-617
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    • 2014
  • The performance of a cognitive radio network (CRN) solely depends on how precisely the secondary users can sense the presence or absence of primary users. The incorporation of a spatial false alarm makes deriving the probability of a correct decision a cumbersome task. Previous literature performed this task for the case of a received signal under a Normal probability density function case. In this paper we enhance the previous work, including the impact of carrier frequency, the gain of antennas on both sides, and antenna heights so as to observe the robustness against noise and interference and to make the correct decision of detection. Three small scale fading channels: Rayleigh, Normal, and Weibull were considered to get the real scenario of a CRN in an urban area. The incorporation of a maximal-ratio combining and selection combing with a variation of the number of received antennas have also been studied in order to achieve the correct decision of spectral sensing, so as to serve the cognitive users. Finally, we applied the above concept to a traffic model of the CRN, which we based on a two-dimensional state transition chain.