• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.17 no.6
• /
• pp.185-201
• /
• 2018

Road lighting is highly preferred as the major nighttime road safety countermeasures. When it comes to the pole-type road lighting, as it's installed at a certain height from the road surface, the driver is dazzled by the light source, interrupting the driver's visibility and furthermore, the light leaks to the area outside the road boundary, worsening the energy efficiency as well as generating the light pollution to the surrounding environment including the animals and plants. The study developed the low-level lighting systems, so it is possible to prevent the lights from being strayed, so there is no any side effects in terms of the sleep deprivation. The study compared the performance as the lightings between low-level lightings and conventional pole based lighting systems. As the results, the low-level lighting systems showed the higher performance in terms of average surface luminance, uniformity, glare compared to the conventional lighting systems.

• Applied Chemistry for Engineering
• /
• v.5 no.4
• /
• pp.706-713
• /
• 1994

Isothermal vapor-Liquid equilibrium data have been measured for binary systems MTBE-methanol, MTBE-n-heptane, and methanol-n-heptane at $45^{\circ}C$ and $65^{\circ}C$ by using head space gas chromato-graphy (H.S.G.C). Among these systems a minimum azeotrope was observed in both of MTBE-methanol system and n-heptane-methanol system. Particularly n-heptane-methanol system has a heterogeneous minimum azotrope since it has an immisible region. These equilibrium data were correlated with the excess Gibbs energy model, and the thermodynamic consistency test was also carried out by using Redlich-Kister equation.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.15 no.6
• /
• pp.2128-2147
• /
• 2021

Cognitive radio systems are being implemented recently to tackle spectrum underutilization problems and aid efficient data traffic. Spectrum sensing is the crucial step in cognitive applications in which cognitive user detects the presence of primary user (PU) in a particular channel thereby switching to another channel for continuous transmission. In cognitive radio systems, the capacity to precisely identify the primary user's signal is essential to secondary user so as to use idle licensed spectrum. Based on the inherent capability, a new spectrum sensing technique is proposed in this paper to identify all types of primary user signals in a cognitive radio condition. Hence, a spectrum sensing algorithm using improved convolutional neural network and long short-term memory (CNN-LSTM) is presented. The principle used in our approach is simulated annealing that discovers reasonable number of neurons for each layer of a completely associated deep neural network to tackle the streamlining issue. The probability of detection is considered as the determining parameter to find the efficiency of the proposed algorithm. Experiments are carried under different signal to noise ratio to indicate better performance of the proposed algorithm. The PU signal will have an associated modulation format and hence identifying the presence of a modulation format itself establishes the presence of PU signal.

• Journal of Applied Reliability
• /
• v.15 no.2
• /
• pp.108-123
• /
• 2015

Test and Evaluation (T&E) have been verifying the level of it's technological skill and the needed operational status of the development weapons. If the overall spectrum of test and evaluation is fulfilled substantially in the production & deployment, the needed level of the weapon system will be enhanced and also the reliability status will become higher considerably. We can know currently these issues through the mass media and all kinds of the news regarding the defense industry and programs. And so this article have studied the method of enhancing reliability of the test and evaluation, the 6 variables were selected through the discussion of the professional group. The the test and evaluation group needs consistently the professional training systems. After DT&E, we have to the event to verify the technical level of the development systems. We have to take the high level of the kinds of the environmental test. Scientific methods like system engineering will be adapted in process of the test and evaluation. The number of suitable test prototype in the test and evaluation is analysed more systematically. And we need to establish the standardization of the test and evaluation. If 6 variables are well analysed and adapted in the working field, the reliability of the test and evaluation will be considerably, the defense industry will take the chance to develope the future-oriented.

• Korean Journal of Environmental Agriculture
• /
• v.30 no.4
• /
• pp.357-366
• /
• 2011

BACKGROUND: Mathematical model such as GLEAMS have been developed and successfully applied to upland fields to estimate the level of pesticide residues in soil. But, the GLEAMS model rarely applied to the Korean conditions. METHODS AND RESULTS: To evaluate pesticide transport in soil residue using the GLEAMS model from pepper plot, Alachlor, Endosulfan, Cypermethrin and Fenvalerate were applied for standard and double rate. Soil sampling was conducted and decaying patterns of pesticides were investigated. Observed climate data such as temperature and irrigation amount were used for hydrology simulation. The observed pesticide residue data of 2008 were used for parameter calibration, and validation of GLEAMS model was conducted with observed data of 2009. After calibration, the $K_{oc}$ (Organic carbon distribution coefficient) and WSHFRC (Washoff fraction) parameters were identified as key parameters. The simulated concentrations of the pesticides except Fenvalerate were sensitive to $K_{oc}$ parameter. Overall, soil residue concentrations of Alachlor, Cypermethrin and Fenvalerate were fairly simulated compared to those of Endosulfan. The applicability of the GLEAMS model was also confirmed by statistical analysis. CONCLUSION(s): GLEAMS model was eligible for evaluation of pesticide soil residue for Alachlor, Cypermethrin and Fenvalerate.

• International Journal of Control, Automation, and Systems
• /
• v.6 no.2
• /
• pp.243-252
• /
• 2008

It has been reported that long-term exercise on a treadmill (running machine) may cause injury to the joints in a human's lower extremities. Previous works related to analysis of human walking motion are, however, mostly based on clinical statistics and experimental methodology. This paper proposes an analytical methodology. Specifically, this work deals with a comparison of normal walking on the ground and walking on a treadmill in regard to the external and internal impulses exerted on the joints of a human's lower extremities. First, a modeling procedure of impulses, impulse geometry, and impulse measure for the human lower extremity model will be briefly introduced and a new impulse measure for analysis of internal impulse is developed. Based on these analytical tools, we analyze the external and internal impulses through a planar 7-linked human lower extremity model. It is shown through simulation that the human walking on a treadmill exhibits greater internal impulses on the knee and ankle joints of the supporting leg when compared to that on the ground. In order to corroborate the effectiveness of the proposed methodology, a force platform was developed to measure the external impulses exerted on the ground for the cases of the normal walking and walking on the treadmill. It is shown that the experimental results correspond well to the simulation results.

• Journal of Korean Institute of Industrial Engineers
• /
• v.30 no.1
• /
• pp.17-26
• /
• 2004

In this study, the usability evaluation of a menu-structure was performed using spreading activation model with respect to human's memory retrieval. Spreading Activation Model is effectively used to understand the process of information retrieval, so it can be used as a theoretical background for modeling of the process of human's information retrieval. For spreading activation test (SAT), subjects were presented with 67 pairs of menu titles, which consist of a menu title in the high level menu item and a menu title for the next lower level menu item, from Korea University's web site. For performance tests, three scenarios were developed with longer reaction times and ambiguous associations found in the SAT to reflect the existing problems of the website. As a result, the SAT was found to bean effective tool to enhance the website usability because the SAT could bea substitute for the performance test with a high correlation $({\rho}=0.735,\;{\alpha}=0.05)$. After remaining menu titles with slow reaction times and ambiguous associations found in SAT, the website usability was significantly improved with faster reaction times and less ambiguous associations proven with smaller number of web-page visits. Therefore, the SAT could be used as a methodology to design and evaluate the user-centered menu structure related to human's association structure.

• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.948-950
• /
• 2003

In this literature, the CMOS current mode fout quadrant differentiator circuit is proposed. The implementation is base on an appropriate input stage that converts the input current into a compressed voltage at the input capacitor ($C_{gs}$) of the CMOS driver circuit. This input voltage use as the control output current which flow to the output node by passing through a MOS active load and use it as the feedback voltage to the input node. Simulation results with level 49 CMOS model of MOSIS are given to demonstrate the correct operation of the proposed configuration. But the gain of the circuit is too low so the output differentiate current also low. The proposed differentiator is expected to find several applications in analog signal processing system.

• 제어로봇시스템학회:학술대회논문집
• /
• 2000.10a
• /
• pp.511-511
• /
• 2000

The equipment is used for testing the electrical characteristics of solar cells that were connected to be a solar panel, which can be found anywhere of solar power plant. This device was built from power switch devices f3r sinking the high current of the solar panel. The processor is a controller, which controls the quantity of the current, which flow through the switching devices and collect the characteristic of the solar panel. The tester can measure the current, voltage, temperature, and light intensity, which are main factors that affect the electrical characteristics of solar cells. 12 bits resolution signal converter is used to change the measuring levels so we can change measuring levels to 4096 levels, and these data are stored in tile memory. The equipment can also calculate the maximum power of the solar system panel.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.7 no.12
• /
• pp.3135-3148
• /
• 2013

The popularization of streaming networks and mobile devices brings a new kind of network called mobile peer-assisted streaming network. In this network, service provider not only offers downloading services, but also pre-pushes resources to users for caching. Users can download their demanded resources while working as servers for uploading the cached data. Also the mobile characteristic makes high package losing probability in this network. So we study how the service provider pre-pushes or the user downloads resources efficiently and effectively while considering the package losing in this paper. We build utility models for service provider and user, and solve the models using Bellman's theory to achieve Nash Equilibrium which shows the service provider's optimal pre-pushing speed and user's optimal downloading speed. The numerical simulation demonstrates the efficiency and effectiveness of our proposed pre-pushing and downloading scheme by comparing to the traditional scheme.