• Title/Summary/Keyword: Environmental control systems

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A Fusion Priority Signal Control Algorithm for Emergency Vehicles (긴급차량 융합형 우선신호 제어 알고리즘 개발)

  • Lee, Soong-bong;Lee, Jin-soo;Jang, Jae-min;Lee, Young-Ihn
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.17 no.2
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    • pp.113-127
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    • 2018
  • This study develops a fusion priority signal control algorithm to pass without delay in emergency events. Fusion priority signal control is method combined center control with local control. The center control method applies signal times for each signalized intersection on the emergency vehicle's route when an emergency call is received. As signals are controlled before the emergency vehicle leaves for its destination, it is possible to clear the queues at each intersection more effectively. However, since the traffic information (speed, position) of the real-time emergency vehicle is not used, the intersection arrival time predicted by center control and actual arrival time of the emergency vehicle may be different from each other. In the case, it is possible to experience a delay caused by the signal. Local control method operate priority signal use the real-time information of EV, but there is a limitation that queue elimination time can not be reflected. In this study, fusion(center+local) control algorithm is proposed to compensate the disadvantages of center and local control also maximizing its advantages. Proposed algorithm is expected to decrease delay time of EV in emergency situation.

A Transdisciplinary Approach for Water Pollution Control: Case Studies on Application of Natural Systems

  • Polprasert, Chongrak;Liamlaem, Warunsak
    • Environmental Engineering Research
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    • v.19 no.3
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    • pp.185-195
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    • 2014
  • Despite the enormous technical and economic efforts to improve environmental conditions, currently about 40% of the global population (or 2 billion people) are still lack access to safe water supply and adequate sanitation facilities. Pollution problems and transmission of water- related diseases will continue to proliferate. The rapid population growth and industrialization will lead to a reduction of arable land, thus exacerbating the food shortage problems and threatening environmental sustainability. Natural systems in this context are a transdisciplinary approach which employs the activities of microbes, soil and/or plants in waste stabilisation and resource recovery without the aid of mechanical or energy-intensive equipments. Examples of these natural systems are: waste stabilisation ponds, aquatic weed ponds, constructed wetlands and land treatment processes. Although they require relatively large land areas, the natural systems could achieve a high degree of waste stabilisation and at the same time, yield potentials for waste recycling through the production of algal protein, fish, crops, and plant biomass. Because of the complex interactions occurring in the natural systems, the existing design procedures are based mainly on empirical or field experience approaches. An integrated kinetic model encompassing the activities of both suspended and biofilm bacteria and some important engineering parameters has been developed which could predict the organic matter degradation in the natural systems satisfactorily.

Tuberculosis Infection Control in Health-Care Facilities: Environmental Control and Personal Protection

  • Lee, Ji Yeon
    • Tuberculosis and Respiratory Diseases
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    • v.79 no.4
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    • pp.234-240
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    • 2016
  • Transmission of tuberculosis (TB) is a recognized risk to patients and healthcare workers in healthcare settings. The literature review suggests that implementation of combination control measures reduces the risk of TB transmission. Guidelines suggest a three-level hierarchy of controls including administrative, environmental, and respiratory protection. Among environmental controls, installation of ventilation systems is a priority because ventilation reduces the number of infectious particles in the air. Natural ventilation is cost-effective but depends on climatic conditions. Supplemented intervention such as air-cleaning methods including high efficiency particulate air filtration and ultraviolet germicidal irradiation should be considered in areas where adequate ventilation is difficult to achieve. Personal protective equipment including particulate respirators provides additional benefit when administrative and environmental controls cannot assure protection.

Development of Algorithms for Four-quadrant Gate System and Obstacle Detection Systems at Crossings (철도건널목 지장물·진입위반차량 검지시스템 및 4분할 차단 알고리즘 개발)

  • Oh, Ju-Taek;Cho, Han-Seon;Lee, Jae-Myung;Shim, Kyu-Don
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.3D
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    • pp.367-374
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    • 2006
  • This research revealed the operation problems of the current crossing control systems through inspecting and testing the obstacle detection systems and gate control systems for the crossings. To resolve the problems of the crossing control systems, this research developed new algorithms of four-quadrant gate system and obstacle detection systems combing the functions of rasar sensors and magnetic sensors and tested the reliability of the systems. Currently, the obstacle detection systems and gate control systems controls approaching and departing traffic by simply detecting vehicles and obstacles but do not consider traffic movements at the crossings. In addition, they do not make signal cooperation for gate controls. As a result, such inefficient crossing controls result in unsafe gate controls for drivers. Therefore, the newly developed crossing control systems through this study will provide more effective crossing control services with more strengthen information cooperation within control systems. Besides they will help to reduce train crashes at the crossings by gate control systems considering various driving behaviors.

Seismic Behavior and Recentering Capability Evaluation of Concentrically Braced Frame Structures using Superelastic Shape Alloy Active Control Bracing System (초탄성 형상기억합금 능동제어 가새시스템을 이용한 중심가새프레임 구조물의 지진거동 및 복원성능 평가)

  • Hu, Jong Wan;Rhee, Doo Jae;Joe, Yang Hee
    • Journal of the Earthquake Engineering Society of Korea
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    • v.16 no.6
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    • pp.1-12
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    • 2012
  • The researches related to active control systems utilizing superelastic shape memory alloys (SMA) have been recently conducted to reduce critical damage due to lateral deformation after severe earthquakes. Although Superelastic SMAs undergo considerable inelastic deformation, they can return to original conditions without heat treatment only after stress removal. We can expect the mitigation of residual deformation owing to inherent recentering characteristics when these smart materials are installed at the part where large deformation is likely to occur. Therefore, the primary purpose of this research is to develop concentrically braced frames (CBFs) with superelastic SMA bracing systems and to evaluate the seismic performance of such frame structures. In order to investigate the inter-story drift response of CBF structures, 3- and 6-story buildings were design according to current design specifications, and then nonlinear time-history analyses were performed on numerical 2D frame models. Based on the numerical analysis results, it can be comparatively verified that the CBFs with superelastic SMA bracing systems have more structural advantages in terms of energy dissipation and recentering behavior than those with conventional steel bracing systems.

Good modeling practice of water treatment processes

  • Suvalija, Suvada;Milisic, Hata;Hadzic, Emina
    • Coupled systems mechanics
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    • v.11 no.1
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    • pp.79-91
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    • 2022
  • Models for water treatment processes include simulation, i.e., modelling of water quality, flow hydraulics, process controls and design. Water treatment processes are inherently dynamic because of the large variations in the influent water flow rate, concentration and composition. Moreover, these variations are to a large extent not possible to control. Mathematical models and computer simulations are essential to describe, predict and control the complicated interactions of the water treatment processes. An accurate description of such systems can therefore result in highly complex models, which may not be very useful from a practical, operational point of view. The main objective is to combine knowledge of the process dynamics with mathematical methods for processes estimation and identification. Good modelling practice is way to obtain this objective and to improve water treatment processes(its understanding, design, control and performance- efficiency). By synthesize of existing knowledge and experience on good modelling practices and principles the aim is to help address the critical strategic gaps and weaknessesin water treatment models application.

Image Feature-Based Real-Time RGB-D 3D SLAM with GPU Acceleration (GPU 가속화를 통한 이미지 특징점 기반 RGB-D 3차원 SLAM)

  • Lee, Donghwa;Kim, Hyongjin;Myung, Hyun
    • Journal of Institute of Control, Robotics and Systems
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    • v.19 no.5
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    • pp.457-461
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    • 2013
  • This paper proposes an image feature-based real-time RGB-D (Red-Green-Blue Depth) 3D SLAM (Simultaneous Localization and Mapping) system. RGB-D data from Kinect style sensors contain a 2D image and per-pixel depth information. 6-DOF (Degree-of-Freedom) visual odometry is obtained through the 3D-RANSAC (RANdom SAmple Consensus) algorithm with 2D image features and depth data. For speed up extraction of features, parallel computation is performed with GPU acceleration. After a feature manager detects a loop closure, a graph-based SLAM algorithm optimizes trajectory of the sensor and builds a 3D point cloud based map.

Real-time Localization of Mobile Robot Using Ultrasonic Sensor in Structured Indoor Environment (구조화된 실내 환경에서 초음파센서를 이용한 모바일 로봇 실시간 localization 기법)

  • Lee Man-Hee;Cho Whang
    • Journal of Institute of Control, Robotics and Systems
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    • v.11 no.12
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    • pp.1068-1076
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    • 2005
  • In order to increase the autonomous navigation capability of a mobile robot, it is very crucial to develop a method for the robot to be able to recognize a priori hon structured environmental characteristics. This paper proposes an ultrasonic sensor based real-time method for recognizing a priori known structured indoor environmental characteristics like a wall and comer Unlike the methods reported in the literature the information obtained from the sensor can be processed in real-time by extended Kalman filter to update estimations of the position and orientation of robot with respect to known environmental characteristics.

Efficiency Comparison between Chlorine and Chlorine Dioxide to Control Bacterial Regrowth in Water Distribution System

  • Lee, Yoon-Jin
    • Journal of Environmental Health Sciences
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    • v.32 no.4 s.91
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    • pp.282-291
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    • 2006
  • This study investigated the inactivation of the total coliform, an indicator organism in chlorine and chlorine in order to control microbial regrowth for water distribution systems and select an appropriate disinfection strategy for drinking water systems. The disinfection effects of chlorine and chlorine dioxide with regard to the dosage of disinfectant, contact time and DOC was investigated experimentally. In spite of the consistency of chlorine residuals at approximately 0.2 mg/l, bacteria regrowth was detected in the distribution system and it was confirmed by the scanning electron microscope results. The influence of organic carbon change on the killing effect of chlorine dioxide was strong.