• International Journal of Automotive Technology
• /
• 제6권2호
• /
• pp.95-105
• /
• 2005

Diesel engines have low specific fuel consumption, but high particulate emissions, mainly soot. Diesel soot is suspected to have significant effects on the health of living beings and might also affect global warming. Hence stringent measures have been put in place in a number of countries and will be even stronger in the near future. Diesel engines require either advanced integrated exhaust after treatment systems or modified engine models to meet the statutory norms. Experimental analysis to study the emission characteristics is a time consuming affair. In such situations, the real picture of engine control can be obtained by the modeling of trend prediction. In this article, an effort has been made to predict emissions smoke and NO$_{x}$ using cylinder combustion derived parameters and diesel particulate filter data, with artificial neural network techniques in MATLAB environment. The model is based on three layer neural network with a back propagation learning algorithm. The training and test data of emissions were collected from experimental set up in the laboratory for different loads. The network is trained to predict the values of emission with training values. Regression analysis between test and predicted value from neural network shows least error. This approach helps in the reduction of the experimentation required to determine the smoke and NO$_{x}$ for the catalyst coated filters.

• 한국표면공학회지
• /
• 제45권2호
• /
• pp.89-94
• /
• 2012

A study to replace a high temperature thermal carbonization process with microwave plasma process is carried for PAN fiber as a starting material. Near atmospheric pressure microwave plasma (1 Torr~45 Torr) was used to control to get the fiber temperature up to $1,000^{\circ}C$. Even argon is an inert gas, its plasma state include high internal energy particles; ion (15.76 eV) and metastable (11.52 eV). They are very effective to lower the necessary thermal temperature for carbonization of PAN fiber and the resultant thermal budget. The carbonization process was confirmed by both EDS (energy dispersive spectroscopy) of plasma treated fibers and OES (optical emission spectroscopy) during processing step as a real time monitoring tool. The same trend of decreasing oxygen content was observed in both diagnostic methods.

• Journal of Electrical Engineering and Technology
• /
• 제7권2호
• /
• pp.141-150
• /
• 2012

The present study examines an efficient congestion management system compatible with the evolving environment. The key is to build an information model shared and exchanged for marketbased solutions to alleviate congestion. Traditional methods for congestion management can be classified into two categories, i.e., the centralized scheme and the decentralized scheme, depending on the extent to which the independent system operator (ISO) is involved in market participants' (MPs) activities. Although the centralized scheme is more appropriate for providing reliable system operation and relieving congestion in near real-time, the decentralized scheme is preferred for supporting efficient market operation. The minimum set of information between the ISO and MPs for decentralized scheme is identified: i) congestion-based zone, ii) Power Transfer Distribution Factors, and iii) transmission congestion cost. The mathematical modeling of the proposed information is expressed, considering its process of making effective use of information. Numerical analysis is conducted to demonstrate both cost minimization from the MP perspective and the reliability enhancement from the ISO perspective based on the proposed information exchange scheme.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2009년도 춘계학술대회 논문집
• /
• pp.105-110
• /
• 2009

Distributed Generation (DG) is predicted to play a important role in electric power system in the near future. insertion of DG system into existing distribution network has great impact on real-time system operation and planning. It is widely accepted that micro turbine generation (MTG) systems are currently attracting lot of attention to meet customers need in the distributed power generation market In order to investigate the performance of MT generation systems, their efficient modeling is required. This paper presents the modeling and simulation of a MT generation system suitable for grid-connected operation. The system comprises of a permanent magnet synchronous generator driven by a MT. A brief description of the overall system is given, and mathematical models for the MT and permanent magnet synchronous generator are presented. Also, the use of Power electronics in conditioning the power output of the generating system is demonstrated. Simulation studies with MATLAB/Simulink have been carried out in grid-connected operation mode of a DG system. The control strategies for grid connected operation mode of DG system is also presented.

• 조명전기설비학회논문지
• /
• 제23권12호
• /
• pp.210-216
• /
• 2009

마이크로그리드는 전력시스템의 계획 및 실시간 운영에 있어서 매우 큰 영향을 미치며 중요한 역할을 할 것으로 판단된다. 따라서 본 연구에서는 빌딩의 마이크로그이드의 중요한 마이크로소오스인 마이크로터빈 발전시스템의 Matlab/Simulink 모델과 전압-주파수제어기를 개발하였다. 또한 부하에 독립적으로 전원을 공급하기 위한 전력시스템을 구성, 모의를 통하여 MTG시스템의 특성을 분석하였다.

• 한국ITS학회 논문지
• /
• 제4권1호
• /
• pp.81-88
• /
• 2005

최근 실시간 교통정보제공이 가능해지고, 사용자간의 커뮤니케이션이 활발해짐에 따라, 사용자간의 협력이 가능해질 것으로 보인다. 만약 이런 상황이 현실화된다면, 사용자간의 비협력을 전제로 하는 Wardrop 의 경로선택원리는 수정이 필요하며, 사용자간의 협력을 균형원리에 포함시킬 필요가 있다. 즉, 사용자간의 협력하에서 경로를 선택하는 원리를 새롭게 정의해야 한다. 본 연구에서는 교통정보를 통해 운전자간의 협력이 가능한 교통망 상황하에서 운전자의 경로선택기준을 제시하는 데 목적이 있다. 이를 Wardrop의 사용자균형(Wardrop User Equilibrium)과는 달리 협력적 사용자균형(Cooperative User Equilibrium)으로 정의하며, 몇 가지 예제를 통하여 이들 두 개의 사용자 균형상태를 분석한 결과, 협력적 균형상태가 Wardrop의 균형상태 보다 더 좋은 해를 찾을 수 있음을 확인할 수 있었다.

• 대한원격탐사학회지
• /
• 제20권1호
• /
• pp.47-55
• /
• 2004

We have constructed a level-1 processor to generate brightness temperatures using the direct-broadcast data from the passive microwave radiometer onboard Aqua satellite. Although 50-minute half-orbit data, called a granule, are being routinely produced by global data centers, to our knowledge, this is the first attempt to process 10-minute long direct-broadcast (DB) data. We found that the processor designed for a granule needs modification to apply to the DB data. The modification includes the correction to path number, the selection of land mask and the manipulation of dummy scans. Pixel-to-pixel comparison with a reference indicates the difference in brightness temperature of about 0.2 K rms and less than 0.05 K mean. The difference comes from the different length of data between 50-minute granule and about 10-minute DB data. In detail, due to the short data length, DB data do not always have correct cold sky mirror count. The DB processing system is automated to enable the near-real time generation of brightness temperatures within 5 minutes after downlink. Through this work, we would be able to enhance the use of AMSR-E data, thus serving the objective of direct-broadcast.

• Smart Structures and Systems
• /
• 제18권3호
• /
• pp.625-642
• /
• 2016

The rapid technology developments in smartphones have created a significant opportunity for their use in structural live load measurements. This paper presents extensive experiments conducted in two stages to investigate this opportunity. Shaking table tests were carried out in the first stage using selected popular smartphones to measure the sinusoidal waves of various frequencies, the sinusoidal sweeping, and earthquake waves. Comparison between smartphone measurements and real inputs showed that the smartphones used in this study gave reliable measurements for harmonic waves in both time and frequency domains. For complex waves, smartphone measurements should be used with caution. In the second stage, three-dimensional motion capture technology was employed to explore the capacity of smartphones for measuring the movement of individuals in walking, bouncing and jumping activities. In these tests, reflective markers were attached to the test subject. The markers' trajectories were recorded by the motion capture system and were taken as references. The smartphone measurements agreed well with the references when the phone was properly fixed. Encouraged by these experimental validation results, smartphones were attached to moving participants of this study. The phones measured the acceleration near the center-of-mass of his or her body. The human-induced loads were then reconstructed by the acceleration measurements in conjunction with a biomechanical model. Satisfactory agreement between the reconstructed forces and that measured by a force plate was observed in several instances, clearly demonstrating the capability of smartphones to accurately assist in obtaining human-induced load measurements.

• Journal of Electrochemical Science and Technology
• /
• 제10권3호
• /
• pp.321-328
• /
• 2019

A new miniaturized all solid-state contact Fe (III)-selective PVC membrane electrode based on Fe (II) phthalocyanine as a neutral carrier was described. The effects of the membrane composition and foreign ions on the electrode performance was investigated. The best performance was obtained with a membrane containing 32% poly (vinyl chloride), 64% dioctylsebacate, 3% Fe (II) phthalocyanine, and 1% potassium tetrakis (p-chlorophenyl) borate. The electrode showed near Nernstian response of $26.04{\pm}0.95mV/decade$ over the wide linear concentration range $1.0{\times}10^{-6}$ to $1.0{\times}10^{-1}M$, and a very low limit of detection $1.8{\pm}0.5{\times}10^{-7}M$. The potentiometric response of the developed electrode was independent at pH 3.5-5.7. The lifetime of the electrode was approximately 3 months and the response time was very short (< 7 s). It exhibited excellent selectivity towards Fe (III) over various cations. The miniaturized all solid-state contact Fe (III)-selective membrane electrode was successfully applied as an indicator electrode for the potentiometric titration of $1.0{\times}10^{-3}M$ Fe (III) ions with a $1.0{\times}10^{-2}M$ EDTA and the direct determination of Fe (III) ions in real water samples.

• 국제초고층학회논문집
• /
• 제8권2호
• /
• pp.117-123
• /
• 2019

Tall buildings are prone to wind-induced vibrations due to their slenderness whereby peak structural accelerations may be higher than the recommended maximum value. The common countermeasure is the installation of a tuned mass damper (TMD) near the highest occupied floor. Due to the extremely large modal mass of tall buildings and because of the narrow to broad band type of wind excitation the TMD mass may become inacceptable large - in extreme cases up to 2000 metric tons. It is therefore a need to develop more efficient TMD concepts which provide the same damping to the building but with reduced mass. The adaptive TMD concept described in this paper represents a solution to this problem. Frequency and damping of the adaptive TMD are controlled in real-time by semi-active oil dampers according to the actual structural acceleration. The resulting enhanced TMD efficiency allows reducing its mass by up to 20% compared to the classical passive TMD. The adaptive TMD system is fully fail-safe thanks to a smart valve system of the semi-active oil dampers. In contrast to active TMD solutions the adaptive TMD is unconditionally stable and its power consumption on the order of 1 kW is negligible small as controllable oil dampers are semi-active devices. The adaptive TMD with reduced mass, stable behavior and lowest power consumption is therefore a preferable and cost saving damping tool for tall buildings.