• Title/Summary/Keyword: frequency problem

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A Study on the Criteria Appropriateness of Experimental Materials & Facilities in Home Economics Education of Secondary School (중등학교 가정과 실험학습 교구.설비기준의 적정성에 관한 연구)

  • 강혜숙;윤인경
    • Journal of Korean Home Economics Education Association
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    • v.5 no.1
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    • pp.61-85
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    • 1993
  • Because of the specificity of subjects belong to middle school curriculum of Home Economics Education of function training is very important. but it pointed out that the existing standards are out-dated, and because of it , it incongruent to our realities. Therefore, whenever the curriculum o education and the national textbook are reorgrnized periodically, the reform of standards of educational materials & facilities must be followed by it. But in my opinion, in korean middle school, especially in Home Economics Education, educational facilities are not reformed at a proper time. Therefore to enhance the qualities of experimentation/practice of Home Economics Education, in the first place, the preparation for the given conditions of standards of educational materials & facilities are needed. But the educational facilities of Home Economics Education have many problem not only in the qualitative aspect but also in the quantitative aspect. And in addition to it, lost of educational facilities which cannot match contents of national textbook of Home Economics Education are exist. Therefore this thesis aims at examining comprehensively the problem of experimentation /practice of experimental materials & facilities of Home Economics Education connect with contents of Home Economics Education, holding several problems of experimentation/practice of Home Economics Education in middle school, grouping ; the principles and ways concerning the innovation experimental materials & facilities of Home Economics Education by which many teachers and students make sure of more efficient teaching/studying, and obtaining basic data which guarantee the ability of innovation concerning problems of the education of experimentation/practice of Home Economics Education. Method are : 1)grasp our educational realities with my original(question). 2)Integrate/analyse results of 1) 3)check the frequency, percentage with methods of X$^2$-test, T-test, and ‘One-way Analysis of Variances’. 4)suggest my own alternative proposal.

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A Study on the Problem Analysis and Improvement Plan for the Korean Railways Communication Networks (국내 철도 통신망의 문제점 분석 및 개선방안 연구)

  • Kim, Kyung-Hee;Kim, Yong-Kyu;Park, Duk-Kyu
    • Journal of the Korean Society for Railway
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    • v.16 no.6
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    • pp.534-539
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    • 2013
  • The research about the Korean integrated wireless network for railways is in progress. The network integrates and complements the various railway functions. In addition, the network is trying to change from wire communication to radio communication. The activities for the railway frequency acquisition are also in progress for the implementation of the network. This paper analyzes the problems for the Korean railway communication networks. The problems revolve around the dispersed network structure, the limited functions, the different communication methods, the technology limitation for the communication methods, and the usage of the non-licensed band. Subsequently, we explain the current state and trend for the foreign communication of the railways. This paper suggests improvement plans for the problems and also explains the expected efficiency for the improvement plans.

A Study on the Fire Alarm System of Vertical Fire Spread Structure by Using FDS (FDS을 이용한 수직 연소확대 구조의 화재경보방식에 관한 연구)

  • Gu, Seon-Hwan;Song, Young-Joo
    • Fire Science and Engineering
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    • v.30 no.5
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    • pp.100-107
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    • 2016
  • Today, high-rise buildings expected to meet various needs and improve the quality of frequency of fire and the potential risks are increasing. In particular, the fire spread risk in the vertical direction is increasing. As a result there is a problem with delays in the evacuation time of occupants. To overcome this problem, there is a need to consider the structure of the building and develop a system for the early detection of fire by applying a fire alarm system according to the risk ranking. Therefore, this paper describes the vertical fire spread characteristics of a multistory double-skin and stairs structure with risk. The data were compared with that from the national and international fire alarms as well as with. smoke density, smoke detectors, visibility, and CO concentration using FDS. A fire alarm system for each structure is proposed.

Evaluation of User Satisfaction for Drink Bottle (음료용기의 사용자 만족도 조사 연구 - Cap이 달린 유리 및 PET용기를 중심으로 -)

  • Kim, Sang-Sik
    • The Journal of the Korea Contents Association
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    • v.6 no.11
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    • pp.172-181
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    • 2006
  • Universal designs begins from observing things. This paper understands contradiction and irrationality about drink bottle used unintentionally in our common life. Those have not found out until now. So an example observation about problem derivation and a practice method of Universal design is presented. People of various classes, such as a child, an old person and a woman, a male, the man in the street, and a disabled person, have been using drink bottle recently. However, the design of drink bottle has become on the basis of the fine and common man, so the other people, for example, children or handicapped persons experience many situations which cannot open cap or cannot be drunk without external help. This research posed questions from the children to the elders about drink bottle by the viewpoint of universal design paying attention to such problems. In the research result, the fixed quantity and qualitative quantity about problem are commented. And the fixed quantity utilized frequency analysis and chi-square verification ($X^2$) for the questionnaire result on the basis, and the qualitative quantity pointed out result in the universal design principle through the data of a precedence research result. An alternative plan for drink bottle's design is presented through case observation of conceptual approach to method of Universal design.

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Deep Learning-based Antenna Selection Scheme for Millimeter-wave Systems in Urban Micro Cell Scenario (도심 Micro 셀 시나리오에서 밀리미터파 시스템을 위한 딥러닝 기반 안테나 선택 기법)

  • Ju, Sang-Lim;Kim, Nam-Il;Kim, Kyung-Seok
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.20 no.5
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    • pp.57-62
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    • 2020
  • The millimeter wave that uses the spectrum in the 30GHz~300GHz band has a shorter wavelength due to its high carrier frequency, so it is suitable for Massive MIMO systems because more antennas can be equipped in the base station. However, since an RF chain is required per antenna, hardware cost and power consumption increase as the number of antennas increases. Therefore, in this paper, we investigate antenna selection schemes to solve this problem. In order to solve the problem of high computational complexity in the exhaustive search based antenna selection scheme, we propose a approach of applying deep learning technology. An best antenna combination is predicted using a DNN model capable of classifying multi-classes. By simulation tests, we compare and evaluate the existing antenna selection schemes and the proposed deep learning-based antenna selection scheme.

Design and Implementation of Efficient PA Technology for Mobile PST (모바일 PST를 위한 효율적 PA 기법 설계 및 구현)

  • Shim, Jae-Sung;Park, Seok-Cheon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.12
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    • pp.3049-3054
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    • 2014
  • PST stands for the Premium Sales Tool for Product Consulting is customized product catalog system. In other words, the product classification categories of content for consulting and sales to customers by providing useful information for the maximization of an overall system. These problems with mobility and flexibility of updating the solution to integrate mobile with mobile devices, but high-performance high-resolutions era content data continuously, but still it is difficult to handle. In this paper, to solve this problem, depending on the user's gesture by allowing periodic allocation and release of a problem for load generation enhanced by improving the PST system has been designed and implemented. Implementation was a result of the test the performance of the system, that PA system that has been provided by the traditional DA system show the allocation and the average 78% of the rate of decrease the load is released in the frequency of page, CPU utilization was reduced an average 72% I was confirmed.

Design of FIR Filters with Finite Precision Coefficients Using LP(Linear Programming) (선형계획을 이용한 유도 정밀도 계수 FIR 필터의 설계)

  • 조남익;이상욱
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.19 no.12
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    • pp.2386-2396
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    • 1994
  • In this paper, an optimal algorithm for the design of 1-D FIR filters with finite precision coefficients is proposed. The algorithm is based on the observation that the frequency constraints of a sub-problems(SP) in the branch and bound algorithm, which repeatedly use LP(linear programming), are closely related with those of neighboring SPs. By using the relationship between the SPs, the proposed algorithm reduces the number of constraints required for solving each SP with Lp, whereas the conventional algorithm employs all the constraints, which are required for solving the initial problem. Thus, the overall computational load for the design of FIR filters with finite precision coefficients is significantly alleviated, compared to the conventional branch and bound algorithm. Also, a new branching scheme for the design of FIR filters with sum-of-power-of-two(SOPOT) coefficients is proposed. It is shown that the computational load for the design fo SOPT coefficient filters can be further reduced with the new branching scheme.

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Adaptive Mitigation of Narrowband Interference in Impulse Radio UWB Systems Using Time-Hopping Sequence Design

  • Khedr, Mohamed E.;El-Helw, Amr;Afifi, Mohamed Hossam
    • Journal of Communications and Networks
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    • v.17 no.6
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    • pp.622-633
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    • 2015
  • The coexistence among different systems is a major problem in communications. Mutual interference between different systems should be analyzed and mitigated before their deployment. The paper focuses on two aspects that have an impact on the system performance. First, the coexistence analysis, i.e. evaluating the mutual interference. Second aspect is the coexistence techniques, i.e. appropriate system modifications that guarantee the simultaneous use of the spectrum by different technologies. In particular, the coexistence problem is analyzed between ultra-wide bandwidth (UWB) and narrow bandwidth (NB) systems emphasizing the role of spectrum sensing to identify and classify the NB interferers that mostly affect the performance of UWB system. A direct sequence (DS)-time hopping (TH) code design technique is used to mitigate the identified NB interference. Due to the severe effect of Narrowband Interference on UWB communications, we propose an UWB transceiver that utilizes spectrum-sensing techniques together with mitigation techniques. The proposed transceiver improves both the UWB and NB systems performance by adaptively reducing the mutual interference. Detection and avoidance method is used where spectrum is sensed every time duration to detect the NB interferer's frequency location and power avoiding it's effect by using the appropriate mitigation technique. Two scenarios are presented to identify, classify, and mitigate NB interferers.

Enhanced Mobile Agent Scheme for RFID Privacy Protection (RFID 프라이버시 보호를 위한 향상된 모바일 에이전트 기법)

  • Kim, Soo-Cheol;Yeo, Sang-Soo;Kim, Sung-Kwon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.2C
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    • pp.208-218
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    • 2008
  • We are sure that RFID system should be a widely used automatic identification system because of its various advantages and applications. However, many people know that invasions of privacy in RFID system is still critical problem that makes it difficult to be used. Many works for solving this problem have focused on light-weight cryptographic functioning in the RFID tag. An agent scheme is another approach that an agent device controls communications between the tag and the reader for protecting privacy. Generally an agent device has strong security modules and enough capability to process high-level cryptographic protocols and can guarantees consumer privacy. In this paper, we present an enhanced mobile agent for RFID privacy protection. In enhanced MARP, we modified some phases of the original MARP to reduce the probability of successful eavesdropping and to reduce the number of tag's protocol participation. And back-end server can authenticate mobile agents more easily using public key cryptography in this scheme. It guarantees not only privacy protection but also preventing forgery.

Association between Oral Health Status and Perceived General Health (EuroQol-5D) (구강건강상태와 감지 건강상태(EuroQol-5D)와의 연관성)

  • Sim, Seon-Ju
    • Journal of dental hygiene science
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    • v.14 no.3
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    • pp.364-370
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    • 2014
  • The purpose of this study was to examine association between oral health status and perceived general health symptom. We analyzed 14,231 subjects who participated in Korea National Health and Nutrition Examination Survey (2007~2009). All individuals were examined by a questionnaire about socioeconomic history, smoking and drinking habit, the frequency of daily tooth brushing, the presence of regular dental visit, and EuroQol-5D. Dental survey was conducted to find the decayed, missing, and filled teeth (DMFT) index and community periodontal index. Subjects with perceived problem with mobility had higher DMFT index (odds ratio, 1.18, p<0.001). Subjects with with perceived problem with pain/discomfort had higher DMFT index (odds ratio, 1.16, p<0.001). Self-rating general health symptom was not associated with periodontitis (p>0.05). Perceived general health was associated with DMFT index. It is recommendable that we can use the perceived general health to predict oral health status.