• 한국컴퓨터정보학회논문지
• /
• 제20권8호
• /
• pp.61-67
• /
• 2015

The existing methods for control between smart devices in near used Bluetooth, WiFi-Direct, or socket communication using Wi-Fi. However, those have a problem that can not use when operating system of each smart devices is different or when socket server is not working. In this paper, we proposed a new near control technology using High frequencies in audible frequency between smart devices to supplement the problem of existing methods. High frequencies use micro-phone and speaker of smart device and are a control signals that is combined high frequencies within 18kHz ~ 22kHz among audible frequency range. The proposed technology using High frequencies do not need any extra communication modules or socket servers and can use the most smart devices without operating system of devices. To evaluate the performance of the proposed technology, we developed a music play and music control application applied the proposed technology and tested a control experiment using the developed applications. The control success rate was 97% and recognition rate of surrounding people about using high frequencies was under 5%. Therefore, the proposed technology will be the useful technology to control between smart devices in near.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2000년도 추계학술대회 논문집
• /
• pp.153-156
• /
• 2000

To reduce the maintenance expense, and the possibility of electric outage and accident, we should optimize the outdoor insulation system. And for the optimization, accurate measurement for the degree of contamination with climatic conditions, such as wind, rain, and drought, should be carried. However the classical measuring method, brush wiping, has some problems in the aspect of man power, reliability, and expense. In this paper, we propose two type apparatus, which could detect the degree of contamination on insulators in outdoor insulation system, such as transmission and distribution line insulator and bushing. One use the leakage current, and the other use the oscillating frequency to check the degree of contamination. To avoid the oxidation of electrode AC source, and the low degree of contamination was applied. From the result of this investigation we could get the good relationship between the degree of contamination and the leakage current and oscillating frequency

• Journal of Magnetics
• /
• 제2권1호
• /
• pp.12-15
• /
• 1997

Fe-(3∼6.5wt%) Si alloy powders having a high magnetic induction(Bs) and a low core loss value for high frequency use were obtained by an extractive melt spinning as well as a centrifugal atomization technique. Sintered core rings made by the rapidly solidified Fe-6.5wt% Si powders exhibited the high frequency magnetic properties : megnetic induction(B8) of 1.23 T, coercivity(Hc) of 0.12 Oe, relative permeability(${\mu}$a) of 6321, and core loss(W10/50) of 1.27 W/kg from the rings of 1.1 mm thick. The magnetic induction values were found to be almost identical to those of non-oriented Fe-6.5wt% Si steel sheet and double the value of 6.5wt% Si sheet prepared by the CVD technique. The high frequency core losses(W) up to 10 kHz(W10/10k) were measured to be competitive to those of grain-oriented Fe-6.5wt% Si steel sheet.

• 한국마린엔지니어링학회:학술대회논문집
• /
• 한국마린엔지니어링학회 2011년도 후기공동학술대회 논문집
• /
• pp.75-75
• /
• 2011

This paper has been studied that ocean wave vibration power generator is composed of buoy and vibration generator to make effective use of ocean wave energy. We designed buoy to can occur resonance for dominant frequency with ocean wave. And then we fitted the natural frequency of vibration system with vibration power generator to buoy's natural frequency. And we can show that the amplitude of ocean wave up and down motion is decreased, on the other hand, the displacement of vibration system with vibration power generator is increased. Therefore, ocean wave vibration power generator which is proposed in this paper has merits not only securing its stability from surroundings but also producing more electronic power by using ocean wave energy.

• 한국측량학회:학술대회논문집
• /
• 한국측량학회 2004년도 추계학술발표회 논문집
• /
• pp.81-86
• /
• 2004

GPS surveying is being applied in earnest in public and construction surveying field recently. However only large enterprise surveying companies have GPS equipments but almost of small companies don't have them because of that their financial status is always too poor to purchase the expensive equipments such as Dual frequency GPS receiver. This is caused by some misunderstanding that only Dual frequency GPS receiver can be used for Public surveying. In order to increase the use of Single frequency GPS receiver to achieve competitive power of small companies in future, we need to verify the applicability and recommend surveyors to use it.

• ETRI Journal
• /
• 제34권4호
• /
• pp.641-644
• /
• 2012

The problem of sinusoidal parameter estimation at two channels with common frequency in white Gaussian noise is addressed. By making use of the linear prediction property, an iterative linear least squares (LLS) algorithm for accurate frequency estimation is devised. The remaining parameters are then determined according to the LLS fit with the use of the frequency estimate. It is proven that the variance of the frequency estimate achieves Cram$\acute{e}$r-Rao lower bound at sufficiently small noise conditions.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2014년도 춘계학술대회
• /
• pp.893-895
• /
• 2014

무선통신기반 열차제어시스템의 국내 도입을 앞두고 철도전용 주파수 할당에 대한 사항이 활발히 논의되고 있다. 공공자원으로서 큰 가치를 지닌 주파수를 적절한 용도에 알맞은 양을 할당하는 것은 다른 분야와의 형평성과 한정된 자원의 유용한 사용 측면에 있어서도 중요한 문제이다. 본 논문에서는 무선통신기반 열차제어시스템에서 기존에 논의되던 서비스들을 LTE 기반의 철도통신망에 적용했을 때 안정적인 운용이 가능한지에 대하여 시뮬레이션을 통하여 알아보았다.

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 1996년도 춘계학술발표회논문집(1)
• /
• pp.587-593
• /
• 1996

Vibration analysis is one of the most powerful tools available for the detection and isolation of incipient faults in mechanical systems. The methods of vibration analysis in use today and under continuous study are broad band vibration monitoring, time domain analysis, and frequency domain analysis. In recent years, great interest has been generated concerning the use of time-frequency representation and its application for a machinery diagnostics and condition monitoring system. The objective of the research described in this paper was to develop a new diagnostic tool for the rotating machinery. This paper introduces a new time-frequency representation, Directional Wigner-Ville Distribution, which analyses the time- frequency structure of the rotating machinery vibration.

• 한국치위생학회지
• /
• 제19권6호
• /
• pp.931-939
• /
• 2019

Objectives: The purpose of this study was to determine the importance of brushing before sleeping by comparing the use of oral care products, frequency of dental clinic visits, and oral conditions between individuals who brush and do not brush their teeth before sleeping using data from the 5th and 6th Korean National Health and Nutrition Survey (KNHANES). Methods: Statistical analysis was performed using SPSS 21.0 on data files obtained according to a complex sampling design, and a significance level of <0.05 was set. General characteristics of the participants and year were analyzed using chi-square analysis. Data on the oral conditions, use of oral care products, and frequency of dental clinic visits were analyzed using logistic regression and linear regression. Results: Individuals who brushed their teeth before sleeping showed greater use of oral care products and more frequent dental clinic visits, oral examinations, preventive treatment, and treatment for simple caries (p<0.05) than individuals who did not. Individuals who did not brush their teeth before sleeping showed higher prevalence of permanent teeth caries and periodontal disease, as well as chewing and speaking problems (p<0.05), than those who bushed before sleeping. Conclusions: Individuals who do not brush before sleeping exhibit poorer oral health and lower use of oral care products and frequency of recent dental treatment than those who brush before sleeping. Therefore, it is necessary to alter the government's active policy and improve education about the importance of brushing before sleeping to improve oral health.

• 대한지역사회영양학회지
• /
• 제16권2호
• /
• pp.227-238
• /
• 2011

To investigate recognition and use of nutrition labeling on eating-out menus, self-recorded questionnaire was surveyed for 641 consumers who visited hamburger and pizza restaurants in Daejeon from May to July, 2010. Subjects were women of 51.3% and 92.9% aged 10s or 20s. Use frequency of hamburger and pizza restaurants was 2-3 times a month with 56.9%. Of subjects 41.0% knew nutrition labeling mandates of eating-out menus, 64.6% have seen nutrition labels of menus, and 44.5% read nutrition labels when purchasing. Among subjects who read nutrition labels, 67.0% (29.8% of total) referred to it when menu purchase and 60.4% (26.9% of total) experienced changing menu. The ratio of reading nutrition labels was different among gender, diet trial frequency and monthly eating-out cost. Reasons for not reading labels were "not interested in" or "never heard about" for 57.0%, and "not noticeable" for 28.7%. The ratio who read correctly all 3 pieces of information, such as calorie amount, daily value, and way of using daily value was 39.2%. Average number of correct reading was 2.13, which was different among gender, marital status, having children, diet trial frequency, monthly eating-out cost, the restaurants use frequency, and accompanying person. Many subjects wanted to be additionally provided with cholesterol and transfat. Therefore, practical and differentiated consumer educations considering consumer features are required for better nutrition labeling usage. Government's regulatory efforts and voluntary effort of eating-out companies, such as adding nutrients on labels and improving labeling places, are also necessary.