• Journal of KIISE:Software and Applications
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• v.35 no.3
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• pp.149-161
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• 2008

As Programmable Logic Controllers(PLCs) are frequently used to implement real-time safety critical software, testing of PLC software is getting more important. We propose a structural testing technique on Function Block Diagram(FBD) which is one of the PLC programming languages. In order to test FBD networks, we define templates for function blocks including timer function blocks and propose an algorithm based on the templates to transform a unit FBD into a flowgraph. We generate test cases by applying existing testing techniques to the generated flowgraph. While the existing FBD testing technique do not consider infernal structure of FBD to generate test cases and can be applied only to FBD from which the specific intermediate model can be generated, this approach has advantages of systematic test case generation considering infernal structure of FBD and applicability to any FBD without regard to its intermediate format. Especially, the proposed method enables FBD networks including timer function blocks to be tested thoroughly. To demonstrate the effectiveness of the proposed method, we use trip logic of bistable processor of digital nuclear power plant protection systems which is being developed in Korea.

• Journal of Intelligence and Information Systems
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• v.17 no.4
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• pp.75-94
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• 2011

In this paper, we explore the information diffusion mechanism under social network environments by investigating the effect of message characteristics on the volume and speed of retweeting in Twitter, a popular online social media service. To this end, we select eight main keywords (i.e., '무상급식', '반값등록금', '나가수', '평창', '김연아', '박태환', '아이폰', '갤럭시') that have been popular on online social media in recent days. Each keyword represents various social aspects of Korea that recently grab people's attention such as political issues, entertainment, sports celebrities, and the latest digital products, and eventually holds distinctive message characteristics. Analyzing the frequency and velocity of retweeting for each keyword, we find that more than half of the sample messages posted on Twitter contain personal opinions for the certain keyword, but we also find that the tweets which include objective messages with hyperlink are the fastest ones when being retweeted by other followers. In overall, when being retweeted, the group of messages related to the certain keyword present distinctive diffusion patterns and speed according to message characteristics. From academic perspective, the findings in the study broaden our theoretical knowledge of information diffusion mechanism over online social media. For practitioners, the results also provide managerial implications regarding how to strategically utilize online social media for marketing communications with customers.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.284-287
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• 2000

Recently, developing medical devices have a tendency becoming the module for satisfying user's mutual complex needs. Because the most effective method for the observation of patients condition a diagnosis and a treatment is collecting data from various devices and controling operation following it. Module tendency is more popular due to manage easily totally many individual systems. This study implemented communication protocol to control by one control system connecting modular medical devices. Implemented system consist of one master module controlling all module and managing communication and many Slave modules. Communication between each modules introduced SPI(Serial Peripheral Interface) among many synchronous serial communication methods for the exact transmission and receipt of data. All communication executes by packet format. This can detect error. And, this protocol introduced PNP(Plug And Play) function that auto-detect connecting or removing module during running. This protocol exactly transmitted and received in faster speed more than 1Mbps. And in practical application to the ventilator this confirmed to give and take real-time data. And various functions by th central control system is implemented in this protocol.

• Cartoon and Animation Studies
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• s.47
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• pp.295-333
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• 2017

This study is a basic study to prepare policies related to selecting media to be included in textbooks. Researchers looked at previous studies focusing on how media affect children's and adolescent's emotions according to their developmental stages. Researchers also wanted to identify how the media is related to student emotions, health, and educational effectiveness. The researchers then examined a wide range of domestic media review and rating criteria, and argued that it is necessary to institutionalize the rating system of media at national level policy level. Based on the previous discussion, the researchers made seven suggestions. First, it is necessary to specify media selection criteria in the guidelines for issuing textbooks at the national level. Second, guidelines are needed to help review the political neutrality and human rights aspects of the media for inclusion in textbooks. Third, media selection guidelines in textbooks should be detailed with reference to categories and age based criteria of domestic and foreign media rating system. Fourth, the media rating system should be applied flexibly if there is a clear educational purpose. Fifth, institutional support is needed for setting guidelines for media collection of textbooks. Sixth, media experts should participate in the whole process of textbook development. Seventh, educational programs should be implemented to support teachers to use self directed learning by using educational media in classroom instruction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.339-344
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• 2016

Since transmissions of large amounts of data are frequent, users require more bandwidth, and the need for communications networks having greater bandwidth is increasing. One communications network satisfying this need is an optical communications network. Therefore, studies to increase the transmission capacity of optical communications systems have been carried out. However, in a general optical communications system, a signal transmitted through optical fiber (a transmission medium) is detected through direct detection in the receiving system. This method has a disadvantage in that the entire bandwidth of the optical signal cannot be utilized. Also, when transmitting an optical signal, there is a problem where the signal-to-noise ratio is affected by neighboring channels. To overcome this situation, various studies are being conducted to minimize the influence of external interference and noise. This paper overcomes the situation by transmitting spectrum-sliced signals using the digital transmission system, FSK. Analyzing the characteristics of the signals detected in the receiver of the optical communications system, Gaussian distribution is used for the PDF of the spectrum-sliced signal, and the signal at the receiving end of the optical communications system is assumed to have a k-square distribution. The results of the analysis confirmed it is better to transmit the spectrally divided signal rather than transmit the laser source.

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.7
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• pp.307-314
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• 2017

Stick-PC is small and portable, So it can be used like a desktop if you connect it to a display device such as a monitor or TV anytime and anywhere. Accordingly, Stick-PC can related to various crimes, and various evidence may remain. Stick-PC uses the same Windows version of the operating system as the regular Desktop, the artifacts to be analyzed are the same. However, unlike the Desktop, it can be used as a meaningful information for forensic investigation if it is possible to identify the actual user and trace the usage by finding the traces of peripheral devices before analyzing the system due to the mobility. In this paper, We presents a method of collecting images using Bootable OS, which is one of the image collection methods of Stick-PC. In addition, we show how to analyze the trace of peripheral connection and network connection trace such as Display, Bluetooth through the registry and event log, and suggest the application method from the forensic point of view through experimental scenario.

• Journal of radiological science and technology
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• v.26 no.2
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• pp.29-35
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• 2003

The purpose of this study was to compare the compression force and thickness of the compressed breast between mediolateral oblique and craniocaudal mammography. This population consisted of 204 paired mediolateral oblique and craniocaudal mammography obtained on one mammographic unit by certified mammography technologists during 2 month period. The women examined were $30{\sim}59$ years old with breast implants, the patients were classified into 3 groups according to age, $30{\sim}39$, $40{\sim}49$, and $50{\sim}59$, prior breast cancer, mastectomy or breast deformity were excluded. The digital readout of compressed breast compression force and thickness was recorded. Mammographic positioning was assessed using standard criteria. The mean compression force of the compressed breast on the craniocaudal projection was less than the mean compression force on the mediolateral projection(14 versus 13.88 daN, p<0.05). The mean thickness of the compressed breast for mediolateral projection was 41.46 mm and that for the craniocaudal projection was 39.50 mm(p<0.05). The compressed breast is higher or thicker on mediolateral oblique than on craniocaudal mammography.

• Korean Journal of Remote Sensing
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• v.29 no.4
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• pp.361-373
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• 2013

The monitoring of urban area, target detection and building reconstruction have been actively studied and investigated since high resolution X-band SAR images could be acquired by airborne and/or satellite SAR systems. This paper describes an efficient approach to reconstruct artificial structures (e.g. apartment, building and house) in urban area using high resolution X-band SAR images. Building footprint was first extracted from 1:25,000 digital topographic map and then a corner line of building was detected by an automatic detecting algorithm. With SAR amplitude images, an initial building height was calculated by the length of layover estimated using KS-test (Kolmogorov-Smirnov test) from the corner line. The interferometric SAR phases were simulated depending on SAR geometry and changable building heights ranging from -10 m to +10 m of the initial building height. With an interferogram from real SAR data set, the simulation results were compared using the method of the phase consistency. One of results can be finally defined as the reconstructed building height. The developed algorithm was applied to repeat-pass TerraSAR-X spotlight mode data set over an apartment complex in Daejeon city, Korea. The final building heights were validated against reference heights extracted from LiDAR DSM, with an RMSE (Root Mean Square Error) of about 1~2m.

• Journal of Broadcast Engineering
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• v.14 no.6
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• pp.733-741
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• 2009

The design rule of digital communication systems is the reliable data transmission with high spectral efficiency and minimum allowable power. This paper suggests the method that saves the average power by implementing a multi-dimensional constellation in case of multi-carrier communication system. By using multi-dimensional constellations we can relocate constellation points in the form of a sphere. If we simply convert the two-dimensional QAM modulation into multi-dimensional QAM, constellation points of 2 N dimensional cube form are made up. Relocating outermost constellation points of 2 N dimensional cube form into low energy constellation points, the constellation of the 2 N-dimensional sphere form is made up which decreases power consumption. In this paper, the multi-dimensional constellations of 2 N-dimensional sphere form are designed from 16-QAM to 2,048-QAM, and power reductions are obtained by comparing constellations of 2-dimensional QAMs and multi-dimensional constellations of 2 N-dimensional sphere form. The result shows that the average power consumption of higher dimensional constellations increases, because the more a dimension elevates, the more the relocatable constellation points increase. But, the increment of the average power savings decreases as the a dimension elevates. The transmission of the data by using multi-dimensional constellations of the sphere form is effective to save the average power consumption with little hardware complexity.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.3
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• pp.421-432
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• 2020

This paper proposes a 2-kW solid-state power amplifier (SSPA) developed by employing power amplifier pallets designed using gallium-nitride high electron mobility transistors, which is used in S-band military radars and to replace existing traveling-wave tube amplifier (TWTA). The SSPA consists of a high-power amplifier module, which combines eight power amplifier pallets, a drive amplifier module, a digital control module, and a power supply unit. First, the amplifier module and component were integrated into a small package to account for space limitations; next, an on-board harmonic filter was fabricated to reject spurious components; and finally, an auto gain control system was designed for various duty ratios because recent military radar systems are all active phase radars using the pulse operation mode. The developed SSPA exhibited a max gain of 48 dB and an output power ranging between 63-63.6 dBm at a frequency band of 3.1 to 3.5 GHz. The auto gain control function showed that the output power is regulated around 63 dBm despite the fluctuation of the input power from 15-20 dBm. Finally, reliability of the developed system was verified through a temperature environment test for nine hours at high (55 ℃) / low (-40℃) temperature profile in accordance with military standard 810. The developed SSPA show better performance such as light weight, high output, high gain, various safety function, low repair cost and short repair time than existing TWTA.