• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.41 no.7
• /
• pp.723-731
• /
• 2016

A core technological base to provide enhanced data rates required by 5G mobile wireless communications is the improved bandwidth efficiency using massive multiple-input multiple-output (MIMO) transmission. MIMO transmission requires the channel estimation using the channel state information reference signaling (CSI-RS) and appropriate beamforming, thus the design of the codebook defining proper beamforming vectors is an important issue. In this paper, we propose a multi-rank codebook based on the discrete Fourier transform (DFT) matrix, by utilizing statistical properties of the channel generated by the spatial channel model (SCM). The proposed method includes a structural change of the precoding matrix indicator (PMI) by considering the phase difference distributions between adjacent antenna elements, as well as the selected codevector characteristics of each transmission layer. Performance gain of the proposed method is evaluated and verified by making the performance comparison to the 3GPP standard codebooks adopted by Long-Term Evolution (LTE) systems.

• Physical Therapy Rehabilitation Science
• /
• v.8 no.4
• /
• pp.218-224
• /
• 2019

Objective: This reliability study examined the effects of applying varying induced inward pressures using a transducer placed at 0° neutral ankle position (NEU) and 15° ankle dorsiflexion (DF) on tibialis anterior (TA) muscle thickness using a custom-made device with a force indicator during rehabilitative ultrasound imaging. Design: Cross-sectional study. Methods: Twenty-four healthy subjects were recruited in this study. Two examiners measured the muscle thickness of the TA at 0° NEU and 15° DF in 3 conditions of inward pressures (1.0 N, 2.0 N, and 4.0 N) using a custom-made holder. The muscle thickness was measured three times for each of the conditions arranged in random order. For intra- and inter-rater reliability, the intraclass correlation coefficients (ICCs) with 95% confidence intervals, standard error of measurement, minimal detectable change, and coefficient of variation were analyzed. One-way repeated measures analysis of variance was conducted for investigating changes of TA muscle thickness according to the inward pressures of the transducers. Results: The intra-rater reliability of TA muscle thickness measurement was excellent (ICC_3,1: 0.92-0.96) for all conditions (at both ankle joint angles per varying inward pressure). Likewise, the inter-rater reliability of TA muscle thickness measurement was excellent (ICC_2,1: 0.89-0.97) under same conditions. The mean of TA thickness showed the trend of decreasing significantly with increased inward pressures at all ankle joint angles (p<0.05). Conclusions: Use of this custom-made device with a force indicator is useful to accomplish the high intra- and inter-rater reliability of TA muscle thickness measurement at both ankle joint angles in reducing the measurement error.

• Journal of Korean Society of Rural Planning
• /
• v.16 no.4
• /
• pp.117-129
• /
• 2010

This study is to make value estimating system to valuate prototype landscape of rural and to derive itemized importance to select priority preservable object The results of the study are summarized as follows, It is examined value estimating standard by analyzing prototype landscape related previous study, law and order. Also, It is derived conclusive prototype landscape value estimating system by doing attribute assessment of preserving objects while surveying the site and interviewing professionals, Value estimating system is classified into five items of physical value which are integration, harmony, diversity, symbolism and aesthetics, The historical-cultural value are divided into four categories which are religious value, originality, historicity and scarcity, The communal values are divided into three categories which are sociality, continuing and regional locality and also divided into three categories which are rarity, primitiveness and diversity as the ecological value, Relative priority of prototype landscape value estimating system result is derived as historical-cultural value as the superior position and physical value, communal value and ecological value as the priority order. In the subordinate, historical categories are derived to be the most valuable and originality, symbolism, integration, regional locality, continuing, harmony, aesthetics, religious value, primitiveness, diversity of physical values and diversity of ecological value in order of the priority assessment The results of the study have the meaning of practical use in prior selection and preservation plan of preserving prototype landscape as practical alternative plan for systematical preservation of damaging prototype landscape.

• Journal of the Korean Geographical Society
• /
• v.45 no.6
• /
• pp.788-805
• /
• 2010

The present USN (Ubiquitous Sensor Networks) node deployment practices have many limitations in terms of positional connectivity. The aim of this research was to minimize a redundancy of USN route nodes, by integrating spatially weighted parameters such as visibility, proximity to cell center, road density, building density and cell overlapping ratio into a comprehensive GIS database. This spatially weighted approach made it possible to reduce the number of route nodes (11) required in the study site as compared to that of the grid network method (24). The field test for RSSI (Received Signal Strength Indicator) indicates that the spatially weighted deployment could comply with the quality assurance standard for node connectivity, and that reduced route nodes do not show a significant degree of signal fluctuation for different site conditions. This study demonstrated that the spatially weighted deployment can be used to minimize a redundancy of USN route nodes in a routine manner, and the quantitative evidence removing a redundancy of USN route nodes could be utilized as major tools to ensure the strong signal in the USN, that is frequently encountered in real applications.

• Korean Journal of Environment and Ecology
• /
• v.24 no.1
• /
• pp.78-86
• /
• 2010

The classification of biotope type in major Korean cities was made based on the land use concept rather than the ecological concept of the land as the habitat of biological communities. Therefore, biotope type need to be reclassified according to ecological concerns and regional characteristics. This study attempts to clearly define various critical concepts regarding the classification of biotope type, such as classification hierarchy, classification criteria, classification factor, classification indicator, classification key, and classification standard. Furthermore, it also attempts to suggest the ways to improve the classification system of biotope type by sampling the cases of major Korean cities. The classification system of biotope type is required to have a coherent system that provides basic guidelines, standards and hierarchy with regard to biotic, abiotic and anthropotic factors, as well as classification indicators and classification keys.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.33 no.3
• /
• pp.103-113
• /
• 2015

This study is an evaluation index development research based on Gyeongju Historic Heritage Sites to identify the attractive Properties of Gyeongju, which decided to competitiveness of the historical city. We got the export Indicator candidate groups by the literature reviews and UNESCO, ICOMOS, and 49 Indicator candidate groups had been selected. In the end, we chose 42 attraction indexes in charm of the cultural heritage side, Cultural heritage tourism resources Side, Restraining force Heritage tourism Side three aspects based on the analysis of Importance(M), Standard deviation(SD), Content Validity Ratio(CVR), Agreement, convergence by using Delphi Technique. We can determine these indicators will be useful basic information, for improving the city's historic attractions. In the future, used these indicators as a basis for Attractions effectiveness evaluation of Gyeongju, Through which the attractions of Gyeongju can be re-recognized.

• Korean Journal of Environmental Biology
• /
• v.23 no.1
• /
• pp.32-46
• /
• 2005

The distribution and standing crop of the phytoplankton were investigated at five freshwater lakes Suwon-si and Pyongtaek-si, Gyeonggi-do from Mar. to Nov., 2003. In this investigation, 199 taxa in total were found and classified as 5 phylums 5 classes 16 orders 26 families 72 genera 167 species 1 subspecies 28 varieties and 3 forms by Engler's classification system. The indicator species of clean water was Cladophora glomerata, which was appeared in Gwanggyo reservoir on September, 2003. Twenty taxa including Oscillatoria chlorina were identified as the indicators of water pollution, and three taxa of cyanophyte were toxic algae. In terms of Yang and Dickman's standard of chlorophyll-a content in eutrophication of water, four lakes including Seo lake were found to be in the hypereutrophic state, and Gwanggyo reservoir was in eutrophic state except in winter.

• Journal of Food Hygiene and Safety
• /
• v.32 no.6
• /
• pp.500-506
• /
• 2017

Kimchi cabbage is one of the four major vegetable crops in Korea. The total annual production of kimchi cabbage, the main material of kimchi, was 20,559 tons in 2015. Kimchi cabbage is one of the majer crops produced by farmers which accounts for about 80% of the total leaf vegetable production in Korea. As the consumption of environmental-friendly agricultural products increases, food safety is one of the major public health concerns. We analyzed the biological hazards of kimchi cabbage produced by two types of cultivation methos such as organic farming and conventional farming using various culture media and microscopy. A total of 432 samples were analysed for presence of sanitary indicator microorganisms (aerobic plate count, coliform count, yeast & mold) and food-borne pathogens (Staphylococcus aureus, environmental Listeria, Bacillus cereus). The population of sanitary indicating microorganisms and food borne pathogens was under 5 Log CFU/g in all tested samples. The results of total microorganism numbers of leaf surface showed a positive correlation to those of soil samples. Additionally, we examined chemical factors such as pesticide residues and heavy metals in soil samples. All tested samples did not shown contamination levels higher than the standard limit.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.46 no.3
• /
• pp.233-238
• /
• 2019

This study aimed to assess the skeletal age of skeletal maturational indicator (SMI) and middle phalanx of the middle finger (MP3) stages and to predict the SMI and MP3 stages corresponding to pubertal growth spurt in boys and girls respectively. The skeletal age was assessed from hand-wrist radiographs of 363 children (182 boys, 181 girls) aged 7 to 16 years by radiologists using the Korean standard bone age chart. Also, SMI and MP3 stages were evaluated from the radiographs. From these records, the mean skeletal age of SMI and MP3 stages was calculated. The stages including pubertal growth spurt were SMI 4 - 5, MP3 FG - G stages in boys and SMI 3 - 4, MP3 F - FG stages in girls.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.61 no.1
• /
• pp.131-144
• /
• 2019

The purpose of study was to determine the hygrophyte index of each plant(HIP) considering the moisture environment condition (MEC) of the native plants on the downstream slope of the fill dam and evaluate its applicability which to develop a method to search for leaks and saturated zones of the fill dam for status evaluation of precision safety diagnosis. The HIP was weighted average and consisted of 19 ranks. The weighted average was calculated according to the following three procedures: First, the linear assumption was made according to the actual habitat environmental conditions, the second one was weighted to 10% of the optimal habitat condition, and finally the average value of the distribution range values. The Hygrophyte index of vegetation at each plot (HIV) was obtained from the Sinheung reservoir (Yesan-gun, Chungcheongnam-do) using the results of vegetation survey of the Sinheung reservoir with precision safety diagnosis and suggested the use of the hygrophyte index of the cultivated vegetation. The average HIP range of plant species that emerged in 50 survey sites on the downstream slope of the Sinheung reservoir is 2.99 to 3.56. The coefficient of variation showed a large difference depending on the appearance of the leakage indicator plant(LIP) species. The range of HIV is 2.80 to 4.26, the mean value is 3.37, standard deviation is 0.37 and the coefficient of variation is 9.7%. As a result, the value of the coefficient of variation showed a large difference depending on the appearance of the plant species.