• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.4
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• pp.299-307
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• 2018

Considering a nonlinear high power amplifier(HPA) and a predistorter, we have designed a four-dimensional 8-ary phase shift keying trellis-coded modulation(4D-8PSK-TCM) system, which is recommended for X-band satellite communications. Subsequently, we have evaluated and analyzed the spectrum, constellation characteristics, and BER performance of the system. In satellite communications, owing to the limited power, nonlinear characteristics that determine the operating point of the HPA must be analyzed because the HPA consumes high power. We herein report the design of the 4D-8PSK-TCM system, with efficiencies of 2 and 2.25 bits/channel-symbol. The simulation results confirmed that a 0.35 roll-off value is effective, considering the low peak-to-average power ratio(PAPR) characteristic and the narrow occupation bandwidth of the spectrum. It also confirmed that approximately 15~20 dB of output backoff(OBO) value is required at the HPA when the predistorter is not used, and approximately 1 dB of the OBO value is required when the predistorter is used.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.7
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• pp.754-759
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• 2015

Nowadays, short distance communication systems with low power energy (LPE) are developed for identification and monitoring of site identification of vessel crews and passengers (SIVCP). LPE communication modules, such as Bluetooth low energy (BLE) and Zigbee, are used for short distance communications with LPE. These modules enable 1:N communications and their popularity is growing since the modules can be mounted on movable objects, such as mobile devices and human body. When these modules are used, the important factor that affects their operation time and design are the capacity and size of battery. Therefore, they must be made as small as possible, and the battery should be selected to be slightly smaller than the module. In this study, we calculate the theoretical life of batteries used in SIVCP BLE modules using data sheet and discharge characteristic graph under the condition of a 1/250 transmission-ratio (TR). We thus calculate experimental life by measuring transmission current for the same TR, and low speed mode current for a 1/5000 TR and measure long-term experimental life using 1/25 TR for days. Through these experiments, we verify experimental methods for the prediction and extension of battery life that would enable us to select appropriate sizes of batteries based on vessel usage and passenger types. The selections of the module TR and battery size are important factors affecting the cost reduction of module design, the battery maintenance, and passenger convenience.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.499-504
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• 2017

A Mobile Radio Wave Measurement System (MRWMS)is a vehicle-mounted system designed to be operating in a single mission. The mission characteristic for mobile measurement requires mobility. For this, we must consider the arrangement and embedded method of MRWMS's antennas. In this paper, we described the measurement method design of direction detecting accuracy for MRWMS and designed the direction finding antenna mast capable of rotating itself by using a slip ring without turntable for Direction Finding (DF) accuracy test. As we removed the dependency of a limited local area by designing a measurement method of direction detecting accuracy, Equipment Under Test (EUT) zero-Adjustment and mounted process shortened. So, we the reduced production costs. We expect an improved cable loss value by shortening the RF cable length in accordance with our design. In addition, due to the same phenomenon, the entire system is lighter and the mobility is improved.

• Journal of Navigation and Port Research
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• v.33 no.10
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• pp.703-707
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• 2009

In order to evaluate applicability of cylindrical slit type block breakwater to the field water, which was designed from the previous physical model study, it is analyzed the calmness of harbor area by the numerical model experiment. For a small fishery port in southern coast of Korea a SWAN model using the wave action balance equation was formulated. The reflection and transmission coefficients induced by the physical model test were introduced to the numerical model. The model response with cylindrical slit type breakwater was compared with the impermeable breakwater case and the possibility of water quality improvement through the water circulation by the new structure was investigated. For numerical simulation, parameters of deepwater design wave from the prediction report II for overall deepwater design wave by KORDI were used and wind parameters from the 50years return period observed for 37years(1970~2006) were adopted in the numerical model. The response of west breakwater in Mijo port applying the NE and NNE waves, which were dominant in this area, was analyzed. It was found that the transmission characteristic of designed cylindrical slit breakwater was well presented in the numerical model.

• Journal of the Korean Society of Costume
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• v.58 no.2
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• pp.62-77
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• 2008

This study aims to analyze color characteristics centered by women's suit styles that represent masculinity remarkably. Through this, it figures out color's type and continuance availability as a representing tool to express masculinity to provide useful color information which can be applied effectively to various color planning. For this research, related images were collected among women's pants suits appeared in $2004{\sim}2006's$ Paris, London, New York and Milan collection F/W that are most similar to modern man's suit. Among them, the study analyzes 319 pictures where the features of masculinity were represented effectively. The referred color values were earned by converting $L^*a^*b^*$ values measured through the color extracting tool of Computer program (Adobe Photoshop CS) and color tone characteristic were analyzed by classifying 12 color PCCS and 5 achromatic colors. The result of the study are as follows: First, based on standard of color hue and tone, in terms of color hue, PB, YR, Y were frequently shown up but G, BG series were not found much after analyzing overall women's pants suit color characteristics shown in $2004{\sim}2006$ Paris, London, New York and Milan collection. Second, the color analysis about 3years of $2004{\sim}2006$ tells that achromatic colors have been most widely used in every year. In terms of color hue, PB, YR, Y series were appeared most popular and G, BG classes weren't appeared frequently. In addition, once looking at yearly color tone distribution trend, like overall color tone distribution result, Bk, w, dkg, g, p were highly used as sequential and b, v, dp, sf, ItGy series show low distribution level. And such a distribution level of low and high in frequency has been showed continuously as a similar style. Accordingly, through the study, as a tool to express masculinity in women's suit, achromatic colors like black and white series and PB, YR, Y series color were investigated as most popular uses. And as color tones, Bk, w, dkg, g, p were used frequently.

• Korean Journal of Oriental Medicine
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• v.13 no.3
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• pp.119-124
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• 2007

Introduction: In Oriental medicine, the status of tongue is the important indicator to diagnose one's health, because it represents physiological and clinicopathological changes of inner parts of the body. The method of tongue diagnosis is not only convenient but also non-invasive, so tongue diagnosis is most widely used in Oriental medicine. By the way, since tongue diagnosis is affected by examination circumstances a lot, its performance depends on a light source, degrees of an angle, a medical doctor's condition etc. Therefore, it is not easy to make an objective and standardized tongue diagnosis. In order to solve this problem, in this study, we tried to design a discriminant function for thick and thin coating with color vectors of preprocessed image. Method: 52 subjects, who were diagnosed as white-coated tongue, were involved. Among them, 45 subjects diagnosed as thin coating and 7 subjects diagnosed as thick coating by oriental medical doctors, and then their tongue images were obtained from a digital tongue diagnosis system. Using those acquired tongue images, we implemented two steps: Preprocessing and image analyzing. The preprocessing part of this method includes histogram equalization and histogram stretching at each color component, especially, intensity and saturation. It makes the difference between tongue substance and tongue coating was more visible, so that we can separate tongue coating easily. Next part, we analyzed the characteristic of color values and found the threshold to divide tongue area into coating area. Then, from tongue coating image, it is possible to extract the variables that were important to classify thick and thin coating. Result : By statistical analysis, two significant vectors, associated with G, were found, which were able to describe the difference between thick and thin coating very well. Using these two variables, we designed the discriminant function for coating classification and examined its performance. As a result, the overall accuracy of thick and thin coating classification was 92.3%. Discussion : From the result, we can expect that the discriminant function is applicable to other coatings in a similar way. Also, it can be used to make an objective and standardized diagnosis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.650-658
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• 2017

A grounding system in a large-scale apartment complex consists of a TT grounding system when viewed in each building unit, but the characteristics of TN grounding system appears when viewed in the total ground system function. Therefore, this study examined the characteristics of a grounding system in a large-scale apartment complex using design draft, field measurements and PSCAD/EMTDC modeling. This paper proposes an algorithm for fault analysis depending on the grounding system structure in large-scale apartment complexes considering the connection of the underground culvert as well as a design algorithm for each grounding system considering the contact voltage and step voltage. The simulation results based on the proposed modeling and algorithm confirmed that it is useful for analyzing the characteristics of a grounding system in a large-scale apartment complex.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.1
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• pp.56-63
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• 2016

In this study, we introduce a design of Fuzzy RBFNNs-based digit recognition system using the incremental-PCA in order to recognize the handwritten digits. The Principal Component Analysis (PCA) is a widely-adopted dimensional reduction algorithm, but it needs high computing overhead for feature extraction in case of using high dimensional images or a large amount of training data. To alleviate such problem, the incremental-PCA is proposed for the computationally efficient processing as well as the incremental learning of high dimensional data in the feature extraction stage. The architecture of Fuzzy Radial Basis Function Neural Networks (RBFNN) consists of three functional modules such as condition, conclusion, and inference part. In the condition part, the input space is partitioned with the use of fuzzy clustering realized by means of the Fuzzy C-Means (FCM) algorithm. Also, it is used instead of gaussian function to consider the characteristic of input data. In the conclusion part, connection weights are used as the extended diverse types in polynomial expression such as constant, linear, quadratic and modified quadratic. Experimental results conducted on the benchmarking MNIST handwritten digit database demonstrate the effectiveness and efficiency of the proposed digit recognition system when compared with other studies.

• Archives of design research
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• v.13 no.1
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• pp.103-110
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• 2000

Hangul came to life as part of the East Asian culture of the Chinese ideograph. Korean letter-culture is starkly different from that of Western letter-culture. In the Orient, letters were sacred and incantory; they were objects of awe, which incorporated elements of the majestic, mysterious, and of ritual. Here we had cultural tradition that acknowledged the intrinsic value of the letters. And it was in this context that Hangul was born as a completely phonetic system of writing. However, the characteristics of Hangul are quite different from those of Chinese ideographs, which are designed to convey a certain meaning. Despite the fact that Hangul is phonetic, its roots lie most definitely in the image of Chinese ideographs. This is something that contrasts with the roots of the Latin alphabet, which have been lost in its long journey of evolution. As a phonetic writing system, a notable characteristic of Hangul is that it has this and the attributes of image. In other words, in that Hangul is a compound, it shares some of the same attributes as Chinese ideographs, but also in that it is a phonetic writing system it is dose to the Latin alphabet. Hangul is definitely a visual writing system that has its origins in the visual culture of Chinese characters as well as being functionally a highly developed phonetic writing system. In short, Hangul has both of these attributes in one writing system. These characteristics of Hangul, for us living in the era of the image, are parts that awaken us to the meaning of existence in our visual culture. Unique among the world's writing systems, the identity of Hangul typography will become none other than the essence of our visual culture.

• Journal of The Korean Society of Grassland and Forage Science
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• v.35 no.1
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• pp.43-49
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• 2015

This experiment was conducted to evaluate the agronomic characteristics and forage productivity of Italian ryegrass cultivars in Yecheon, Kyeongbuk from 2011 to 2013. The experimental design was a randomized complete block design (RCBD) with three replications. Italian ryegrass cultivars were seeded on Sep. 26 in 2011 and Sep. 25 in 2012. The Italian ryegrass cultivars were harvested on the heading date of the variety. The cold-resistance of domestic cultivars was stronger than other foreign varieties. Among early-maturing cultivars, the dry matter (DM) yield of the "Kowinearly" was 10,031 kg/ha, which was significantly higher than that of other cultivars (p<0.05). In medium-maturing cultivars, the DM yield of the "Kowinmaster" and "Tam 90" were 10,484 and 8,191 kg/ha, respectively. Of the two, the former's DM yield was higher than the latter's (p<0.05). Among late-maturing cultivars, the DM yield of "Hwasan 104" was 10,641 kg/ha, which was similar to that of "Hwasan 101" and significantly higher than the other late-maturing cultivars (p<0.05). According to the results obtained from this study, an early-maturing variety with cold-tolerance and high productivity is required for the paddy field cultivation of an Italian ryegrass cultivar after rice harvest in the mid-northern region of Korea. A medium- or late-maturing variety is more advantageous for the field cultivation of the maximum quantity that is possible. In conclusion, to select which variety/ies to grow, the climate of the growing area, weather conditions, and the cropping system must all be considered.