• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.7
• /
• pp.3188-3193
• /
• 2012

It is important to search a pitch for vocoder. The major drawback to vocoders is their large computational requirements in searching a pitch and a codebook. In this paper, a simple method is proposed to improve the pitch searching process in the pitch filter almost without degradation of quality. The period of speech signal is emphasized by using Dual Pulse technique, the same type of autocorrelation method, in pitch search. Sometimes the incorrect pitch can be obtained by halving, doubling and trifling, To solve it, before searching a pitch, we estimate energy rate in a frame and compensate envelop of signal with it. By using the proposed algorithm in pitch search, its required computation are reduced and searching pitch is improved.

• Journal of dental hygiene science
• /
• v.10 no.5
• /
• pp.329-334
• /
• 2010

This study was performed to identify the relationship between scaling behaviors and knowledge about scaling and oral health belief of worker, and to provide baseline data for developing industry oral health policy. The survey had conducted self-administered questionnaires by 326 workers in Gyeongsan and Yeongcheon areas in Gyeongbuk province. Their scaling behaviors, knowledge and oral health belief were measured. The results were as follow; The average score of knowledge about scaling was 6.44. The average oral health belief was 2.72. In detail, 'usefulness' was 3.24 as the highest and 'seriousness' was 2.25 as the lowest. The periodic scaling and scaling cycle were associated with 'seriousness' and 'barrier' as positive correlation(p<.05, .01). On the other hand, they were associated with knowledge and 'usefulness' as negative correlation(p<.01). Meanwhile, scaling motive showed positive correlation with 'cue of action'(p<.01), showed negative correlation with knowledge(p<.01). In the correlation between knowledge about scaling and oral health belief, knowledge showed negative correlation with 'barrier'(p<.01) and showed positive correlation with 'usefulness'(p<.01). Finally, we need to advertise and manage the importance of scaling politically and makes people do the voluntary scaling in six-month intervals in order to keep the periodontal health of worker.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.41 no.7
• /
• pp.732-737
• /
• 2016

A pulse radar signal exhibits periodic appearance of pulses in time. So it leads to a high correlation between two samples separated in time by multiples of its period. In this paper, we present a spectrum sensing technique for a radar signal which exploits the periodicity of its autocorrelation function and a radar pulse interval estimation scheme in order to address the case that the radar pulse interval is not known a priori. Finally, we evaluate the sensing performance of the proposed scheme through computer simulation and compare its performances with those of energy detection.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.34 no.2
• /
• pp.190-195
• /
• 2005

The purpose of this study was to identify the change of energy intake, blood sugar and body composition in accordance with menstrual cycle among the women with the premenstrual dysphoric disorder (PMDD) group and women with no premenstrual symptoms (NPS) group. Energy and carbohydrate intake were significantly increased in luteal and menstrual phases than follicular phase in both groups. Protein intake was significantly increased in luteal phase than follicular phase in both of groups. Fat intake was not difference in according to the menstrual phases in both groups. Weight and body water were significantly increased in luteal and menstrual phases than follicular phase in both groups. Fat mass was significantly increased in luteal phase than follicular phase in both groups. However, the differences in energy, carbohydrate, protein and fat intake, weight, body water and fat mass between groups were not significant. Above finding of this study showed that women's energy intake and body composition have connection with change of menstrual cycle and implied that more systematic study which affects menstrual cycle is requested.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2019.05a
• /
• pp.230-230
• /
• 2019

대규모순환패턴과 같은 기후시스템에서의 상태와 변화를 정량화하여 나타낸 기상인자는 수문기상학적 변수와 밀접한 연관이 있는 것으로 알려져 있으며, 이에 따라 비정상성 빈도해석의 수행에 있어서 확률분포모형의 매개변수에 대한 공변량으로 널리 활용되고 있다. 본 연구에서는 비정상성 강우빈도해석 시 매개변수의 공변량으로 우리나라의 극치강우의 장기경향성을 잘 반영할 수 있는 기상인자를 선정하고자 한다. 먼저, 시계열자료를 주기성을 가지는 내재모드함수와 장기경향성을 나타내는 잔여값으로 분해할 수 있는 앙상블 경험적 모드분해법을 이용하여 우리나라 전역에 분포된 61개 지점에서 관측된 연 최대치 강우자료의 평균 및 분산에 대한 잔여값을 추출하였다. 다음으로 11개의 월 단위 기상인자에 대한 계절별 연 평균 시계열과 추출된 평균 및 분산의 잔여값과의 상관계수를 산정하였다. 그 결과, 11개의 기상인자 중 Atlantic Meridional Mode (AMM), Atlantic Multi-decadal Oscillation (AMO), North Atlantic Oscillation (NAO)가 우리나라 연 최대치 강우자료의 평균 및 분산에 대한 장기경향성과 높은 상관성이 있는 것으로 나타났다. 계절적으로는 AMM과 AMO의 경우 이전 년도 가을철 평균이 전 지점 평균 약 0.6, NAO는 이전 년도 여름철 평균이 전 지점 평균 0.3 이상의 유의한 상관계수를 가지는 것으로 나타났다.

• Journal of Biomedical Engineering Research
• /
• v.20 no.5
• /
• pp.573-579
• /
• 1999

본 논문은 2채널 센서를 이용한 펄스 옥시메터의 산소포화도 계산 모델의 설계 및 분석에 관한 것이었다. 또한 Beer Lambert 법칙에 의거하여 기존 알고리즘 및 새로운 알고리즘들을 이론적으로 분석하였다. 제안된 알고리즘은 손가락을 투과한 2개의 채널에서 나온 광신호를 각각 직류성분 Adc 와 맥동성문 Aasin wt. 잡음성분 Ahnoise , ALnoise 등으로 모델링한다. 모델링 되어진 광신호를 맥동성분이 적분비를 사용하여 고주파 동잡음인 AHnoise 를 제거한 후 각각 산소포화도 계산을 위한 상관계수 그래프를 구한다. 또한 2개의 채널에서 적분비를 사용하여 구해진 상관계수 그래프를 사용하여 산소농도를 추출하는 방법에 관하여 기술하였다. 맥동성분비와 관혈적인 측정에 의한 혈중 산소포화도와의 상관관계 그래프의 선형성을 확보하기 위하여 펄스 옥시메터 시뮬레이터 오차범위를 고려해 75~100%상이의 산소포화도를 중점적으로 관측하였고, 4주기로 면적계산주기를 결정하여 실험하였다. 본 연구에서 제안된 알고리즘의 성능평가는 맥동성분의 적분비를 이용한 방법과 비교하였다. 비교결과는 4주기의 면적계산 주기를 가졌을 때 기존의 방식보다 평균오차가 0.7%정도 향상되었으며, 회귀적선의 신뢰도를 보여주는 결정계수 ${\gamma}$$^2$도 0.995로 기존의 방식에서 나온 0.979보다 더 좋은 결과를 얻을 수 있었다. 따라서 2채널을 이용한 방법이 A Lnoise 제거와 성능면에서 우수하다는 결론을 얻을 수 있었다.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.28 no.2B
• /
• pp.237-248
• /
• 2008

Precipitation variability in Korea is mainly influenced by climate circulation such as sea surface temperature, not a local convection. Therefore, this study investigates relationship between monthly precipitation of 61 station observed by Korea Meteorological Administration and global sea surface temperatures (SSTs). The main components of monthly precipitation in Korea are extracted by a method which consists of the principal analysis combined with the cluster analysis, to examine the correlation between monthly rainfalls and SSTs. The relationships between main components of monthly precipitation and SSTs exists in Pacific Ocean. At the result of Wavelet Transform analysis, The 2-4 year band have a strong wavelet power spectrum and the low frequency. the correlation coefficient between low frequency components of monthly rainfalls and SSTs calculated bigger then correlation coefficient between main components and SSTs. Hence, these results propose a prediction possibility of monthly precipitations using the varition of SSTs.

• Journal of Wetlands Research
• /
• v.14 no.4
• /
• pp.503-518
• /
• 2012

Models estimating carbon budget at land surface are mainly interested in vertical flux of carbon. On the other hand, studies on horizontal flux are obviously lacked to confirm that relationship between the hydrological flux of organic carbon discharged from catchment and terrestrial carbon production, a relation between Total Organic Carbon(TOC) and Gross Primary Production(GPP) tried analysis through cross correlation. The best correlation structure is correlation between GPP and TOC of flow-weighted mean concentration from watershed without delay. Furthermore, cross correlation analysis was performed by consider periodicity. The correlation between TOC and GPP in summer was similar to correlation without periodicity. Therefore, correlation between GPP and TOC was most regulated by the correlation between GPP and TOC at summer. As a result, the vegetation carbon and organic carbon from watershed is recognized a close relationship on the seasonal. Therefore, future research is correlation analyzing between vegetation variables according season, GPP and TOC, we are expected to use quantitative understanding that horizontal flux flow of carbon from the surface.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.31 no.2
• /
• pp.73-87
• /
• 2019

Ocean waves are the driving force for the sediment transport and the beach process. However, wave actions are nonlinear and non-stationary, and the response of the beach is inconsistent in terms of reaction rate and magnitude. Therefore, the beach process is difficult to predict accurately. The purpose of this study is to identify the correlations between the shoreline change and ocean waves observed in the east coast of Korea. The relation of the beach width obtained from video monitoring at five sandy beaches and the wave data obtained from nearby wave monitoring at three points was analyzed. Although the correlations estimated over the whole data sets was not significant, the correlations estimated based on the seasonal period or wave conditions provided more noteworthy information. When the non-exceedance probability of the wave height was greater than 0.99, the wave period and beach width showed strong negative correlations. In case the non-exceedance probability of the wave period was greater than 0.99, the wave height and beach width showed strong negative correlations as well. Furthermore, the erosion rate of the beach width increased when the primary wave direction was close to normal to the coastline. Little significant seasonal or monthly change was found between the beach width and the wave, but it was greatly affected by intensive events such as typhoons. Thus, it is necessary to analyze in detail the wave height or period level explaining the change of beach width for more relevant and practical information.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.20 no.1
• /
• pp.48-55
• /
• 2016

The assessment and prediction of service life of a structure are usually under uncertainty so that rational probabilistic concepts and methods have to be applied. Based on these rational assessment and prediction, optimum maintenance strategies to minimize the life-cycle cost and/or maximize the structural safety can be established. The service life assessment and prediction considering maintenance actions generally includes effects of maintenance types and times of the structural components on the service life extensions of structural system. Existing researches on the service life management have revealed the appropriate system modeling considering the correlation among the components is required for system reliability analysis and probabilistic service life estimation. However, the study on correlation among the maintenance actions is still required. This paper deals with such a study for more effective and efficient service life management. In this paper, both the preventive and essential maintenances are considered for the extended service life estimation and management.