• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.61 no.9
• /
• pp.1380-1386
• /
• 2012

It is important to consider supply voltage stability in case of design and construction of a substation at electric railway because a urban transit is operated by electricity and it is driven simultaneous in the same section. This paper study on variation of the dynamic characteristic of supply voltage according to the track environment and spatial distribution as driving of urban transits. Simulation tool, TOM(Train Operations Model) software is used to ensure stability of feeder system being used around the world. As results of simulation, voltage of the contact wire is in limits on driving operation diagram of urban transits. Also, it has confirmed that there is a correlation the phase current, depending on the speed of urban transit and track environment like vertical gradients and curve radius.

• Proceedings of the Korea Contents Association Conference
• /
• 2008.05a
• /
• pp.754-758
• /
• 2008

Since our country is rapidly progressing from an aging society to an advanced age society, it already puts in effect basic old-age pension system, hurries training human resources like care-giver, and has ahead offering the aged long-term care insurance. But our country still needs to develop a systematic curriculum in order to train professionals that can fundamentally deal with an aging society problems. In this paper, therefore, we describe the development of a curriculum for training silver-care professionals improving qualities of old person life in order to suit to an aged society and prepare for an advanced age society. It includes a network model of a silver-care curriculum based on subject classifications according to fields and levels.

• Proceedings of the KIEE Conference
• /
• 2001.07d
• /
• pp.1964-1966
• /
• 2001

Active Noise control(ANC) is rapidly becoming the most effective way to reduce noises that can otherwise be very difficult and expensive to control. This research presents ANFIS (Adaptive Network Fuzzy Inference System) controller for adaptively noise cancelling in a duct. ANC system generates secondary control sound pressure with same amplitude and with opposite phase as noise to be eliminated. ANFIS controller is trained to optimize its parameters for adaptively cancelling noise. That is ANFIS train its parameters by gradient descent and LSE method so called hybrid method. This paper present ANFIS in active noise control which provides an improvement convergence speed and limitation of linearity condition. It can model nonlinear functions of arbitrary complexity and ANFIS can construct an input-ouput mapping based on both human knowledge in the form of Takagi and Sugeno's fuzzy if-then rules and stipulated input-output data pairs. This paper also shows that the proposed ANFIS active noise control system successfully cancelled noise.

• Journal of the Korean Society for Precision Engineering
• /
• v.30 no.10
• /
• pp.1051-1059
• /
• 2013

In general, lateral ride comfort of railway vehicle is mainly influenced by a secondary suspension placed between the bogie and carbody. Higher operating speeds of train results in increased vibration of carbody, which has a negative impact related to the ride comfort. To solve this problem, researches to replace the conventional passive suspension with (semi)active technology in the secondary suspension of a railway vehicle have been carried out. The semi-active suspension using the magneto-rheological damper is relatively simpler system and has advantage in maintenance compared to the hydraulic type semi-active damper. This study was performed to reduce lateral vibration acceleration of carbody related to ride comfort of railway vehicles with a semi-active suspension system. The numerical analysis was conducted by replacing passive lateral damper with semi-active MR damper, and robust control with the MR damper was applied to the 1/5 scaled railway vehicle model.

• Journal of the Korean Society for Precision Engineering
• /
• v.17 no.11
• /
• pp.176-184
• /
• 2000

Recently, it becomes a very important issue to consider the mechanical systems such as high-speed vehicle and railway train moving on a flexible beam structure. Using general approach proposed in the first part of this paper, it tis possible to predict planar motion of constrained mechanical system and elastic structure with various kinds of foundation supporting condition. Combined differential-algebraic equations of motion derived from both multibody dynamics theory and Finite Element Method can be analyzed numerically using generalized coordinate partitioning algorithm. To verify the validity of this approach, results from simply supported elastic beam subjected to a moving load are compared with exact solution from a reference. Finally, parameter study is conducted for a moving vehicle model on a simply supported 3-span bridge.

• Journal of Radiation Industry
• /
• v.11 no.1
• /
• pp.33-38
• /
• 2017

RI-Biomics technology is advanced convergence technologies that can be measured in real time and track in vivo behavior and metabolism of substances using characteristics of the radioactive isotope. Its application fields are increasing such as drug development, agriculture, development of new materials and their utilization, etc. In addition, according to domestic and international developments and changes in the RI-Biomics environment, RI-Biomics professionals are needed to train continuously. To develop systematic human resources basement and competency-based curriculum, we perform competency modeling of pedagogical perspective to targeted at high-performance on RI-Biomics. Furthermore, we redefine the competency model and verified by industry experts with focus group interviews. In the result, two general competencies and three professional competencies were extracted by interview. Each competencies are organized six sub-competencies and nine sub-competencies. In the finial steps, the same procedures were repeated to obtain the consensus of experts on derived competencies and behavioral objectives. The results of the study are applicable to enhance human resource management and to develop the curriculum for RI-Biomics expert training. It is expected to be used as reference material of long term-planning for RI-Biomics professional.

• International Journal of Internet, Broadcasting and Communication
• /
• v.11 no.4
• /
• pp.26-30
• /
• 2019

This paper proposes a new voice activity detection (VAD) method which is based on SNR and non-intrusive speech intelligibility estimation. In the conventional SNR-based VAD methods, voice activity probability is obtained by estimating frame-wise SNR at each spectral component. However these methods lack performance in various noisy environments. We devise a hybrid VAD method that uses non-intrusive speech intelligibility estimation as well as SNR estimation, where the speech intelligibility score is estimated based on deep neural network. In order to train model parameters of deep neural network, we use MFCC vector and the intrusive speech intelligibility score, STOI (Short-Time Objective Intelligent Measure), as input and output, respectively. We developed speech presence measure to classify each noisy frame as voice or non-voice by calculating the weighted average of the estimated STOI value and the conventional SNR-based VAD value at each frame. Experimental results show that the proposed method has better performance than the conventional VAD method in various noisy environments, especially when the SNR is very low.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.20 no.4
• /
• pp.19-25
• /
• 2016

Using a actuator to which the motor and the gear is applied to the I-PD control method and a dual-loop system to carry out precise position control. I-PD control algorithm performs an operation to reduce the overshoot in the transient response. Accordingly, the actuator obtains a precise position tracking result. Also it utilizes two sensors and dual loops. It reduces the adverse effect on the precise position control that may occur by the end play of the gear train. In this paper, we uses the actuator model applying the BLDC motor and gear in order to determine the position tracking result by the dynamic characteristic change. It was verified by the simulation results.

• Proceedings of the KSR Conference
• /
• 2008.11b
• /
• pp.1078-1083
• /
• 2008

In this paper, assessed are the stability of vehicle and track according to vertical support stiffness difference on the transition between conventional and zero-longitudinal resistance (ZLR) rail fastener on bridge. For this, the spring constants of rail fastener have been determined according to different load ranges - KTX load (with or without impact factor) and test load of EN standards - from results of laboratory test on rail pad, the stability analysis of vehicle and track has been performed according to numbers or installation length of ZLR fasteners using vertical vehicle-track coupled model to consider train-track interaction. The analysis results reveal that only the wheel load variation slightly exceed the limit value when 2 ZLR fasteners are used with spring constant determined within the EN test load range, but, in all other cases, all evaluation items are satisfied. Thus, it can be said that the stability of vehicle and track will not be degraded by ZLR fastener.

• Proceedings of the KSR Conference
• /
• 2008.11b
• /
• pp.1776-1781
• /
• 2008

To reduce interior noise of running vehicles, a floating floor construction has been widely used in recent railway industry. Among the key factors of the floating floor design, dynamic stiffness is of most important in acoustical point of view. Sometimes hard rubber type supports have often been selected due to the other design constraints such as heavy load condition, durability of rubber element and its cost etc., even though it seems like the softer support, the better isolation of noise and vibration. In this paper two representative floor supports have been considered to evaluate their effectiveness in interior noise contribution: one is a soft rubber and another is a relatively hard one. From the measured dynamic stiffness of the specimens, equivalent stiffness of actual floating floor has been derived to use in the analytical models. Calculated air-borne and structure-borne noise insulation properties of the floating floors have been compared with experiments in prototype car. In full car model interior noise levels of running vehicles have been predicted to quantify the effectiveness of the two different floating support materials and verified through the measured inside noise levels of actual train as well. By comparison with difference of running noise levels two materials for floor support can be investigated quantitatively so that it could be applied in floating floor design.