• Journal of Satellite, Information and Communications
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• v.8 no.1
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• pp.8-13
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• 2013

It is necessary to develop the next generation FTS which is suitable for our environment and effectively operates many launch vehicles. Standard tone, Secure tone, MHA, EFTS and DSSS are studied for the next generation FTS. FTS requires a high quality of performance and reliability because of their specific mission. And few FTSs are needed but the price is very expensive. Therefore we must investigate a part of the FTS whether the part can be reused for a part of the next FTS. In this paper, we use CCDF of the transmitted signal from FTS as the method to study a possibility of reusing HPA used in the present system. The simulation results show that PEP of Standard tone is 0.21dB and Secure tone and MHA has the same PEP. CPFSK's PEP is 1.81dB and PEP of DSSS using BPSK modulation is 2.6dB.

• Aerospace Engineering and Technology
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• v.13 no.1
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• pp.55-62
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• 2014

FTSR(Flight Termination System Receiver) is a device that receives a ground command signal to abort a flight mission when abnormal conditions occur in the space launch vehicle. The secure tone command message shall consist of a series of 11 character tone pattern. Each character consists of the sum of two tones which taken from a set of 7 tones defined by IRIG(Inter-Range Instrumentation Group) in the audio frequency range. The MHA(Modified High alphabet) command adds a security feature to the secure tone command by using the predefined difference code. In order to check the function and performance of MHA FTSR, which is under development, for KSLV-II, the testbed should have functions of RF signal generation, receiver's output port monitoring, RS-422 communication and test data management. In this paper, we first briefly introduce MHA command and FTSR interface, and then show the LavVIEW based testbed include its H/W configuration, S/W implementation and test results.

• Journal of Fashion Business
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• v.18 no.6
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• pp.174-187
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• 2014

This study intended to propose a guideline designed to secure safety by developing a functional color design for the color of the ordinary working clothes worn in the actual industrial settings of the machine industry in national industrial complexes in Korea. For this, a total of 6 sets of actual working clothes were produced for test, using 2-color arrangements with blue, of varying brightness and chroma for top and bottom, in relation to the visibility proven in preceding studies and evaluated in the machine industry. Blue was suggested the best proper color for machine industry by previous studies. For the material of working clothes, a total of 111 swatches were collected from the Dongdaemoon Fabric Market, and they were analyzed for color values. A total of 6 materials were used to produce working clothes for testing, which represented high brightness, medium brightness, low brightness, high chroma, medium chroma, and low chroma. Clothes were tried at the industrial settings for machine industry in a national industrial complex located in Gyeongsangnam-do and the expert satisfaction evaluation was performed based on items related with safety. As a result, higher satisfaction was shown when the brightness difference of top and bottom clothes was greater, and for chroma, relatively higher satisfaction appeared when the chroma of both top and bottom clothes was high. To secure satisfaction for both brightness and chroma, it is possible to deduce that the 2-color arrangement using the strong tone with high brightness and high chroma and the dark tone with somewhat low brightness and high chroma would be effective. Top and bottom clothes in the same color with high chroma had high visibility but had somewhat low evaluation for harmonious arrangements. This indicated that the arrangement of vivid colors for top-bottom clothes is inappropriate.

• Journal of Satellite, Information and Communications
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• v.8 no.2
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• pp.94-98
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• 2013

A report of security problems and simultaneous operation limits of Standard tone currently used for FTS introduces the development of a next generation FTS. In this paper, BER performance by modulations and channel coding methods for EFTS are compared. Simulation results show that coherent modulations have better BER performance than noncoherent modulations. However the environments of a lunching vehicle may cause serious problems in achieving and maintaining synchronization and the increasing complexity of coherent systems also increases reliability problems. Therefore noncoherent systems are suitable for FTS even though BER performace of noncoherent systems is lower than coherent systems. Noncoherent DPSK has better BER performance than noncoherent CPFSK. However the PEP of noncoherent DPSK is 0.8dB higher than noncoherent CPFSK. Therefore a transmitter of noncoherent DPSK has more output power than noncoherent CPFSK. Convoltional code has better BER performance than RS code. However RS code has a tendency of steeply decreasing BER near the wanted $E_b/N_0$.

• Journal of the Korean Society of Clothing and Textiles
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• v.34 no.3
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• pp.540-552
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• 2010

This research forms preliminary data for the coordination of environmental color planning in industry through a color analysis of work clothes and the work environment. A digital camera was used to study the work environment of two major shipbuilding companies located in Geoje city and Goseong county. The picture data was analyzed as G (ground: environment) and F (figure: clothes), and analyzed hue, value, and the chroma value through a Muncell conversion 9.0.6 from the color cluster, number of pixel, and RGB value. The results are as follows: First, GY, Y color were mostly used in the shipbuilding environment and work clothes. The color value was used in a relatively wide range but very low chroma (0-3), dark grayish, grayish tone dominated both fields. Second, the use of limited colors cannot be secured for safety in attention of the shipbuilding field. Third, unclear and vogue colors lessened the optical tiredness of workers that helped in the prevention of industrial accidents. Color combination and color selection should be considered for a secure safety color coordination between work clothes and the work environment when it comes to complicated color principles.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.5
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• pp.1-12
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• 2015

In this study, we derive an evaluation structure and 18 Valuation vocabulary for the media facade lighting conditions. In addition, this study deduced the applicable elements that could be applied in time of building nightscape lighting design using media facade by conducting affective evaluation. The research results are as follows: It was found that the image axis of "Dynamic, Colorful" showed the lighting change speed was fast with diverse application of lighting color, and its evaluation object applied by general emphasis, vertical emphasis, partial emphasis lighting method was highly assessed. In addition, it was found that "Luxurious, Unusual" axis showed lighting change speed was slow with the application of lighting color in warm hue series, and its evaluation object applied by line lighting, dot lighting, general emphasis lighting methods was highly assessed. Lastly, it was found that "Soft, Secure" image axis showed the lighting change speed was slow with the application of pastel tone lighting color, and the evaluation object applied by general emphasis lighting method was highly assessed.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.1
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• pp.65-75
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• 2011

Power Line Communication (PLC) is a system for carrying data on a conductor used for electric power transmission. Recently, PLC has received much attention due to connection efficiency and possibility of extension. It can be used for not only alternative communication, in which communication line is not sufficient, but also for communication between home appliances. Korea Electronic Power Cooperation (KEPCO) is constructing the system, which automatically collects values of power consumption of every household. Due to the randomness and complicated physical characteristics of PLC protocol (KS X4600-1), it has been believed that the current PLC is secure in the sense that it is hard that an attacker guesses or modifies the value of power consumption. However, we show that the randomness of the protocol is closely related to state of the communication line and thus anyone can easily guess the randomness by checking the state of the communication line. In order to analyze the security of PLC, we study the protocol in detail and show some vulnerability. In addition, we suggest that PLC needs more secure protocol on higher layers. We expect that the study of PLC help in designing more secure protocol as well.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.1
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• pp.132-139
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• 2016

This study was carried out near the waters of Jango port, Dangjin-gun, Chungcheongnam-do by utilizing 10kHz carrier frequency, for the purpose of measurement and analysis of underwater channel environment of the Western sea. For the measurement of horizontal channel environment, the separation distance between transmitter and receiver is made differently in the range between 10m and 4000m. Meanwhile, for the measurement of vertical channel environment, transmission and receiving side ships are fixed as contacted each other and measured differently depending on their depth of submergence. In this study, the Coherence Bandwidth and the Coherence Time were estimated by analyzing the Power delay profile of the real sea based on the measured data, and analyzing the doppler frequency through frequency conversion of received tone-signal, respectively. This study is expected to become a base study in carrying out the frame design for underwater communication to improve the communication and secure the reliability of communication in future underwater channel environment.

• Journal of the Korean Society of Radiology
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• v.18 no.5
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• pp.473-481
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• 2024

As a result of measuring and evaluating 24 units of 10 types of medical ultrasonic equipment in Gwangju using the multipurpose ultrasonic phantom (ATS-539), all 24 units were 100% passed in the non-inspection area, vertical distance measurement, horizontal distance measurement, axial/side resolution, gray tone and dynamic range items. As a result of analyzing the ultrasonic phantom pass rate according to the number of years of use of ultrasonic equipment in Gwangju, this study derived that the service life of ultrasonic equipment is related to the equipment performance. As the coverage for ultrasonic inspection is gradually expanded starting with the upper abdominal ultrasound, it is time to further manage the quality of ultrasonic inspection. Therefore, in addition to the standard guidelines for performance measurement for abdominal inspection, research on equipment phantom measurement methods and standards that can be used in various ultrasonic inspection areas such as the neck and chest, which have recently become increasingly important in clinical practice, should be conducted at the same time. In addition, quality control standards should be legally established to maintain the optimal performance of ultrasonic imaging devices and to secure the appropriateness of images. In addition, ultrasound imaging devices should be classified as special medical equipment, and it is considered that the level of equipment should be consistently maintained through continuous management so that images beneficial to treatment can be obtained.