• Nuclear Engineering and Technology
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• v.33 no.5
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• pp.514-525
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• 2001

Optimum characteristics of digital X-ray sensor components were analyzed to develop intra- oral dental digital X-ray image sensor using indirect method. Parametric analysis was carried out to optimize the phosphor thickness and the fiber optic plate (FOP) coupling to charge coupled device (CCD). X-ray absorption and light diffusion in the phosphor layer were analyzed by the Monte Carlo method. Real time X-ray image was obtained with prototype X- ray image sensor using general CCD camera with 1∼10 Ip/mm resolution. It has been previously shown that large resolution degradation in X-ray images was caused by miss alignment of FOP to CCD and optical adhesive selection. In this study, we reported that X-ray image quality was greatly improved by using optimized characteristics of alignment device and phosphor thickness.

• Journal of Korea Multimedia Society
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• v.20 no.4
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• pp.721-729
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• 2017

This study examined the dramatic devices that the production team made for the studio progress in the survival music entertainment program of open narrative structure in which the audience participated through MBC 'The King of Mask Singer'. The reason for the need for dramatic equipment is that the studio Audience who participated in the process of the program crossed the situations of flow, selection, and enjoyment. As a result of the research, the production team of 'The King of Mask Singer' was found to have a device of time margin, lighting and background image, and role of MC in order to change the progress of the studio and that the participating audience naturally change their roles.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.349-352
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• 2003

A personal low-frequency stimulator is a portable device to relax muscle pains of a person. The stimulator generates combined low-frequency pulses to be applied to pads attached to painful muscles. This paper reports a development of such device with its characteristic analyses. The major components of our stimulator are MCU, high-voltage generating circuit part, high-voltage switching circuit part, input switch part and display unit. High-voltage generating circuit is designed by using a boost converter circuit and allows user control of the output voltage. High-voltage switching circuit, controlled by MCU, generates output voltage to be applied to pads. Input switch part is composed of power supply, intensity selection, mode selection and memory. Display unit adopts a text LCD module to display modes, Intensity, output frequency and user set-up time. Our designed safety circuit, to protect human body from possible electric shock, slowly increases the output voltage to the selected output intensity. It continuously checks the output pulse shape and disable the output when dangerous pulses are detected. This paper also shows some experimental results.

• Korean Journal of Cognitive Science
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• v.11 no.2
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• pp.37-51
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• 2000

The present study compared computer users target-selection response patterns when the targets were varied in terms of their relative location and distance from the current position of the cursor. In Experiment 1, where the mouse was used as an input device, the effects of different directions and distances of simple target(small rectangle) on target-selection response were investigated. The results of Experiment 1 can be summarized as follows: (1) Overshooting was more frequent than either undershooting or correct movement and (2) this tendency was more prominent when the targets were presented in the oblique direction or in farther location from the current cursor position. (3) Although the overshooting and undershooting were more frequent in the oblique direction, the degree of deviation was larger in horizontal and vertical direction. (4) Time spent in moving the mouse rather than that spent in planning, calibrating or clicking was found to be the most critical factor in determining total response time. In Experiment 2, effects of the font size and line-height of the target on target-selection response were compared with regard to two types of input devices(keyboard vs. mouse). The results are as follows: (1) Mouse generally yielded shorter target-selection time than keyboard. but this tendency was reversed when the targets were presented in horizontal and vertical directions. (2) In general, target-selection time was the longest in the condition of font size of 10 and line-height of 100%, and the shortest in the condition of font size of 12 and line-height of 150%. (3) When keyboard was used as the input device, target-selection time was shortest in the 150% line-height condition, whereas in the mouse condition, target-selection time tended to be increased as the line-height increased. which resulted in the significant interaction effect between input device and line-height. Finally, several issues relating to human-computer interaction were discussed based on the results of the present study.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.12
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• pp.4269-4292
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• 2014

Currently, increasing numbers of access points (AP) are being deployed in enterprise offices, campuses and municipal downtowns for flexible Internet connectivity, but most of these access points are idle or redundant most of the time, which causes significant energy waste. Therefore, with respect to power conservation, applying energy efficient strategies in WIFI networks is strongly advocated. One feasible method is dynamically managing network resources, particularly APs, by powering devices on or off. However, when an AP is powered on, the device is initialized through a long boot time, during which period clients cannot be associated with it; therefore, the network performance would be greatly impacted. In this paper, based on a global view of an entire WLAN, we propose an AP selection technology, known as Temporary Access Selection (TAS). The criterion of TAS is a fusion metric consisting of two evaluation indexes which are based on throughput and battery life, respectively. TAS is both service and clients' preference specific through balancing the data rate, battery life and packet size. TAS also works well independently in traditional WLANs in which no energy efficient strategy is deployed. Moreover, this paper demonstrates the feasibility and performance of TAS through experiments and simulations with Network Simulator version 3 (NS3).

• Journal of Korean Clinical Nursing Research
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• v.23 no.3
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• pp.361-375
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• 2017

Purpose: This study was conducted to update the existing nursing practice guideline for intravenous infusion guidelines according to the evidence-based practice guideline in South Korea. Methods: Guideline update process was performed using 22 steps according to the manuals developed by NICE and SIGN. Results: Updated nursing practice guidelines for the intravenous infusion were consisted of 23 domains and 322 recommendations. The number of recommendations in each domain were 4 for general instruction, 12 for vascular access device selection, 20 for site selection, 9 for insertion, 54 for stabilization, 21 for maintaining patency, 4 for blood sampling, 33 for exchange and removal, 28 for add-on device selection, 28, 72 for infusion related complications, 56 for infusion therapies, 7 for education, and 2 for documentation and report. There were 15.9% of A, 30.2% of B, 53.9% of C in terms of grade recommendations. A total of 178 (51.6%) recommendations were newly developed and 24 previous recommendations have been deleted. Conclusion: Updated nursing practice guideline for intravenous infusion was expected to be an evidence-based practice guideline for intravenous infusion in South Korea. This guideline is suggested to be disseminated to clinical nursing settings nationwide to improve the efficiency of intravenous infusion practice.

• Journal of IKEEE
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• v.20 no.2
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• pp.128-135
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• 2016

Smart care surveillance system provides the services to track users automatically by using the nearest CCTV cameras which are capable of monitoring them after the system searches for CCTV cameras around them by using the GPS location information received from them. Because users send their GPS location information with using their smart device when they are in emergency situation or want to be cared for, they may expect quick response of helper in this system. However, in the previous system, the selection time of camera which is capable of monitoring is increased rapidly as the management area is expended because the area management server selects the camera by sorting the distance between all of CCTV cameras and users, and then monitors them whenever they send the location information. In this paper, we propose the method to reduce the selection time of the CCTV cameras for tracking the users by searching only the cameras near to the CCTV cameras used to track them.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.11
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• pp.1500-1506
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• 2020

In this paper, we study a scheduling problem based on reinforcement learning for overlay device-to-device (D2D) communication networks. Even though various technologies for D2D communication networks using Q-learning, which is one of reinforcement learning models, have been studied, Q-learning causes a tremendous complexity as the number of states and actions increases. In order to solve this problem, D2D communication technologies based on Deep Q Network (DQN) have been studied. In this paper, we thus design a DQN model by considering the characteristics of wireless communication systems, and propose a distributed scheduling scheme based on the DQN model that can reduce feedback and signaling overhead. The proposed model trains all parameters in a centralized manner, and transfers the final trained parameters to all mobiles. All mobiles individually determine their actions by using the transferred parameters. We analyze the performance of the proposed scheme by computer simulation and compare it with optimal scheme, opportunistic selection scheme and full transmission scheme.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.6
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• pp.49-56
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• 2015

For designing working devices of construction equipment, it is necessary to consider not only sufficient working ability but also available working range. Therefore, it is important to select the appropriate pivot positions of links. This paper presents a study on selection of pivot points of links used in construction equipment. To analyze the effect of each pivot point, a design program for pivot selection is developed. A conventional pivot design method requires a complicated process because it needs to create a certain working position manually to evaluate its performance. However, the developed program includes an automatic link assembly algorithm; thus, the working device can easily be analyzed by using pivot information of links. The developed program also included a kinematic/static analysis module and characteristic analysis algorithms. Therefore, it is possible to easily analyze a working device model created through the automatic assembly algorithm, whereby users can easily analyze the effect of each link pivot point for the actual product design.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.3
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• pp.577-584
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• 2017

Long Term Evolution device-to-device (LTE D2D) is a key technology to mitigate data traffic load in a cellular system. It facilitates direct data exchange between neighboring users, which is preceded by D2D discovery. Each device advertises its presence to neighboring devices by broadcasting its discovery message. In this paper, we develop a mathematical analysis to assess the probability that discovery messages are successfully transmitted at the D2D discovery stage. We make use of stochastic geometry for modeling spatial statistics of nodes in a two dimensional space. It reflects signal to noise plus interference ratio (SINR) degradation due to resource collision and in-band emission, which leads to the discovery message reception probability being modeled as a function of the distance between the transmitter and the receiver. Numerical results verify that the newly developed analysis accurately estimates discovery message reception probabilities of nodes at the D2D discovery stage.