• Title/Summary/Keyword: frequency problem

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Design of Improved DFT-s-SSB OFDM and Spectral Efficiency in Multiuser Environment (개선된 DFT-s-SSB OFDM 설계와 다수 사용자 환경에서의 스펙트럼 효율)

  • An, Changyoung;Lee, Jungu;Jang, Kyeongsoo;Ryu, Heung-Gyoon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.29 no.3
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    • pp.192-199
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    • 2018
  • This paper proposes an improved discrete Fourier transform spread single sideband(DFT-s-SSB) orthogonal frequency division multiplexing(OFDM) system that solves the problems of conventional DFT-s-SSB OFDM systems. Conventional DFT-s-SSB systems use pulse amplitude modulation(PAM) for applying SSB modulation. The higher the modulation level, the worse is the BER performance. Further, transmission is possible only through the lower sideband(LSB) spectrum. When transmitting using the LSB and upper sideband(USB) spectra simultaneously, interference occurs and spectrum recovery is not performed correctly. To solve this problem, the proposed system applies the 2/3 convolution coding to improve the bit error rate(BER) performance, adjusts the DFT size, and selects the USB spectrum to utilize the remaining spectrum resources. In addition, when using this system in an environment that supports multiuser or limited bandwidth, it uses only half of the spectrum; therefore, it can utilize the remaining spectrum resources and improve the spectral efficiency.

-A Survey on Fool Intakes by Patrons at Tourist Buffet Restaurant- (관광부페 식당 끽식자의 섭식실태에 관한 사례연구)

  • 모수미
    • Journal of the Korean Home Economics Association
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    • v.29 no.2
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    • pp.65-75
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    • 1991
  • A Survey was conducted to identify patrcis' eating behavior at the buffet styled restaurant during dinner time. The average frequency of taking food was 4.1±0.9 and this was statistically significant by age group. The frequency of taking food after satiety was 1.2±0.8. From the menu, 15 seafood items were the most popular which were chosen more than twice. The average of consumed food items was 24.9±8.9 out of 198. The average seafood items which were chosen by each individual was 5.8, desert items was 4.5, salad items with dressing was 4.2. The total weight of the consumed food was 954±365.1g. Mostly gruel, soup and saled chosen the first time. Alcholic beverages and drinks were chosen also first time. Seafood was chosen the 1.2 times and meat was chosen the first, second, and third time. Rice and soup. bread and noodles were chosen the second and third time. Desert was chosen the third time. The consumption of calories and nutrients were compared with the Korean Recommended Dietary Allowances. The average consumption of calories was 49.6% Korean RDAs, protein 71.4%, vitamin A 65.0%, thiamin 74.3%, riboflavin 71.8%, niacin 89.8%, ascorbic acid 72.7%, iron 68.1%, and calcium 108.3%. In one meal, the data shows over eating. The caloric consumption of desert was 275.5Kcal and seafood was 174.1Kcal. The protein consumption of seafood was 23.5g and meat was 7.5g. According to this research, customers have a lot of good chances to be exposed to the variety of food. This is desirable to correct the food habits with a experience. On the other hand, excessive food consumption is a problem. Therefore we suggest the provision of nutrition information about desirable order of eating a meal and the health problems due to overeating. We expect other research of nutritional evaluation in a meal in the different foodservice systems to be made in the future.

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Frequent Pattern Mining By using a Completeness for BigData (빅데이터에 대한 Completeness를 이용한 빈발 패턴 마이닝)

  • Park, In-Kyu
    • Journal of Korea Game Society
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    • v.18 no.2
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    • pp.121-130
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    • 2018
  • Most of those studies use frequency, the number of times a pattern appears in a transaction database, as the key measure for pattern interestingness. It prerequisites that any interesting pattern should occupy a maximum portion of the transactions it appears. But in our real world scenarios the completeness of any pattern is more likely to become various in transactions. Hence, we should also consider the problem of finding the qualified patterns with the significant values of the weighted support by completeness in order to reduce the loss of information within any pattern in transaction. In these pattern recommendation applications, patterns with higher completeness may lead to higher recall while patterns with higher completeness may lead to higher recall while patterns with higher frequency lead to higher precision. In this paper, we propose a measure of weighted support and completeness and an algorithm WSCFPM(weigted support and completeness frequent pattern mining). Our algorithm handles the invalidation of the monotone or anti-monotone property which does not hold on completeness. Extensive performance analysis show that our algorithm is very efficient and scalable for word pattern mining.

A Grading Method for Student′s Achievements Based on the Clustering Technique (클러스터링에 기반한 학업성적의 등급화 방법)

  • Park, Eun-Jin;Chung, Hong;Jang, Duk-Sung
    • Journal of the Korean Institute of Intelligent Systems
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    • v.12 no.2
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    • pp.151-156
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    • 2002
  • There are two methods in evaluation student s achievement. The two evaluation methods are absolute evaluation and relative evaluation. They have much advantages respectively, but also have some limitations such as being too stereotyped or causing overcompetition among learners. This paper suggests a new evaluation method which evaluates student s achievements by considering the score distribution and the frequency The proposed method classifies the scores into several clusters considering the goodness. This approach calculates the goodness by applying the RE(relaxation error), and grades the achievement scores based on the goodness. The suggested method can avoid the problem of grading caused by the narrow gap of scores because it sets a standard for grading by the calculated goodness considering the score distribution and frequency of occurrence. The method can differentiate achievements of a school from those of others, and that it is useful for selecting advanced students and dull ones, and for evaluation of classes based on student s achievement.

An Analysis of Comparison between Autogenes Training and Imaginary Meditation by Heart Rate Variability and SCL-90-R (심박변이도 및 SCL-90-R 측정을 통한 자율훈련법과 과일 명상의 효과 비교 분석)

  • Suh, Jin-Woo;Kim, Jong-Woo;Chung, Sun-Yong;Kim, Ji-Young;Hwang, Eun-Young
    • Journal of Oriental Neuropsychiatry
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    • v.19 no.3
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    • pp.35-44
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    • 2008
  • Objective: There are many meditation methods used in clinical field. But the effect of meditation may be different to people's mind, and meditation itself. Now we investigate this subject with two different meditation methods which has been analyzed by heart rate variability. Method: We tried to check people's heart rate who educated meditation, before educated and during the meditation. The meditation was educated differently for each group. One is the auto genes traning, and the other is the imaginary meditation by thinking about eating and smelling favorite fruits. All of them are used to oriental psychiatry clinic patients. And we simultaneously conduct people's emotional state by SCL-90-R. Result: The result in Autogene traning group has significant difference in total power and HRV-index score between before and during the training but in imaginary meditation group has no significance: Autogene traning group has a significance in low frequency score and has increased tendency with increasing tendency of Heart rate index and Total power. Through the SCL-90-R score, the higher depression t-score, the anxiety t-score, and the hostility score is, the HRV scores such as total power, low frequency, and HRV-index much increase. and so on. Conclusion: We can guess that the Autogenes training has more significant effect than the imaginary meditation. And we can also guess that as the emotional problem is getting more severe, the effect of meditation would be much better. And we finally suggest that we should make a standard guideline of imaginary meditation, cause the imaginary meditation has so many variation.

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Form-finding of Tensegrity Systems by using Frequency Constraints (진동수 목적함수를 이용한 텐세그리티 시스템의 형상탐색기법)

  • Lee, Seung Hye;Lee, Jae Hong;Kang, Joo Won
    • Journal of Korean Society of Steel Construction
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    • v.28 no.5
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    • pp.337-344
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    • 2016
  • In this study, a form-finding method of tensegrity systems by using the force density method combined with the stiffness matrix method was presented. Numerous studies have been made on form-finding methods of the tensegrity systems. However, these methods are limited in the tensegrity systems with multiple null space of the equilibrium matrix. The proposed method can uniquely define a single integral feasible set of force densities for the structures. In order to draw maximum natural frequency that can lead a maximum stiffness of the tensegrity systems, a constrained maximization problem is formulated in the genetic algorithm. Several numerical examples are presented to prove dfficiency in searching for self-equilibrium congifurations of tensegrity systems with multiple self-stress states. A good performance of the proposed method has been shown in the results.

STUDY ON THE CERTIFICATING METHOD OF GPS DATA QUALITY

  • Yeh Ta-Kang;Chen Chun-Sung;Wang Cheng-Gi;Liou Yuei-An;Wang Chuan-Sheng
    • Proceedings of the KSRS Conference
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    • 2005.10a
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    • pp.353-356
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    • 2005
  • In Taiwan, there are more the one hundred GPS tracking stations maintained by Ministry of the Interior (MOI), Academia Sinica, Central Weather Bureau and Central Geological Survey. In the further, they may be instead of the GPS controlling points after giving the lawful status. In other words, the engineers don't need to survey on the reference points when they are surveying in the field. They only need to download the GPS data via internet and process the observations in their company. The precise coordinates of the unknown points will be obtained. Therefore, the data qualities of the tracking stations are more and more important. In this study, six data quality indexes were adopted as follows: observations, cycle slips, multipath on L1, multipath on L2, clock offset and frequency stability. Besides, the relationships of the indexes and the positioning precision were found. The frequency stability of GPS receiver is the most important index, the cycle slip is the second index and the mutlipath is the third index. According to the results, the auto-analytical system of GPS data quality was established and the tracking stations were monitored. When the receiver got some problem or the station's environment changed, we hope to find and resolve the problems earlier to make sure the high data quality of the tracking stations. Moreover, we try to design a data quality verification to help users and let the engineers have more and more confidence when they use the data of GPS tracking stations.

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Analysis of Oriental Obesity Pattern Identification Questionnaire on Overweight and Obese Korean Adult Women (과체중 및 비만 성인 여성의 비만변증 설문 결과 분석)

  • Hwang, Mi-Ja;Moon, Jin-Seok;Park, Kyoung-Su;Song, Mi-Yeon
    • Journal of Korean Medicine for Obesity Research
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    • v.8 no.2
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    • pp.63-72
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    • 2008
  • Objectives We aimed to explore obesity pattern among overweight and obese Korean adult women using oriental obesity pattern identification questionnaire. Methods This survey was performed using data of 83 overweight and obese women aged from 20 to 55 yrs (BMI ${\geq}\;23\;kg/m^2$ : n=18, BMI ${\geq}\;25\;kg/m^2$ :n=65) in Seoul, from 2007 to 2008. Subjects were given written consent and this study was performed under the permission of institutional review board of Kyung-Hee East-west Neo Medical Center. Results 1. The distribution of oriental obesity pattern identification did not show any differences between obese and overweight group(p>0.05). 2. The ratio of significantly-scored oriental pattern identification was ordered by Stagnation of the liver Qi(肝欝, 21.7%) > Indigestion(食積, 18.1%) > Spleen deficiency(脾虚, 16.9%) > Yang deficiency(陽虚, 14.5%) (n=83). 3. The frequency of top-scored oriental obesity pattern was ordered by Stagnation of the liver Qi(肝欝, 36.1%) > Indigestion(食積, 24.1%) > Yang deficiency (陽虚, 15.7%) (n=83). 4. The frequency of oriental obesity pattern identification was ordered by Stagnation of the liver Qi(肝欝, 41.7%) > Indigestion(食積, 29.2%) > Yang deficiency(陽虚, 12.5%) > Stagnation of the liver Qi and Yang deficiency(肝欝兼陽虚, 8.3%) (n=24). Conclusions In Korean adult overweight and obese women, Stagnation of the liver Qi(肝欝), Indigestion(食積), and Yang deficiency (陽虚) were found to be the main pathology based on oriental obesity pattern identification questionnaire. It suggests that not only physical status but also general condition and emotional problem should be concerned in treatment of obesity. This study could play a role as a preliminary data of oriental obesity pattern identification.

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An Efficient Bit Loading Algorithm for OFDM-based Wireless LAN systems and Hardware Architecture Design (OFDM 기반의 무선 LAN 시스템을 위한 효율적인 비트 로딩 알고리즘 및 하드웨어 구조 설계)

  • 강희윤;손병직;정윤호;김근회;김재석
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.41 no.5
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    • pp.153-160
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    • 2004
  • In this paper, we propose an efficient bit loading algorithm for IEEE 802.11a wireless LAN systems. While a conventional bit loading algorithm uses the SNR value of each subcarrier, it is very difficult to estimate the exact SNR value in wireless LAN systems due to randomness of AWGN. Therefore, in order to solve this problem our proposed algorithm uses the channel frequency response instead of the SNR of each subcarrier. Through simulation results, we can obtain the performance gain of 3.5∼8㏈ at PER of 10-2 with the proposed bit loading algorithm while the conventional one obtains the performance gain of 0.5∼5㏈ at the same conditions. Also, the increased data rate can be confirmed 63Mbps. After the logic synthesis using 0.3${\mu}{\textrm}{m}$ CMOS technology, the logic gate count for the processor with proposed algorithm can be reduced by 34% in comparison with the conventional one.

Still Image Identifier based over Low-frequency Area (저역주파수 영역 기반 정지영상 식별자)

  • Park, Je-Ho
    • Journal of Digital Contents Society
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    • v.11 no.3
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    • pp.393-398
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    • 2010
  • Composite and compact devices equipped with the functionality of digital still image acquisition, such as cellular phones and MP3 players are widely available to common users. In addition, the application of digital still images is becoming common among security and digital recording devices. The amount of still images, that are maintained or shared in personal storage or massive storage provided by various web services, are rapidly increasing. These still images are bound with file names or identifiers that are provided arbitrarily by users or that are generated from device specific naming method. However, those identifiers are vulnerable for unexpected changing or eliminating so that it becomes a problem in still image search or management. In this paper, we propose a method for still image identifier generation that is created from the still image internal information.