• The Journal of the Acoustical Society of Korea
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• v.38 no.5
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• pp.580-586
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• 2019

In this paper, we propose a biomimetic communication method using a dolphin whistle to covertly transmit the communication signal. A conventional CSS (Chirp Spread Spectrum) modulation technique divides dolphin whistle into several slots and modulates with up and down chirp signals. That causes the time-frequency characteristic difference between the original dolphin whistle and the camouflage performance is degraded. In this paper, we propose a delay based modulation scheme to eliminate distortions. The simulation results show that the bit error rate of the proposed method is better performance than that of the conventional CSS modulation method by about 3.5 dB to 8 dB. And the camouflage performance that evaluated through the cross correlation in the time-frequency domain is also better than that of the CSS modulation method.

• Speech Sciences
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• v.9 no.3
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• pp.3-16
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• 2002

We examined some problems in speaker identification procedures: transformation of acoustic parameters into auditory scales, invalid measurement values, and comparability of spectral energy values across the frequency range. To resolve those problems, we analyzed the acoustic spectral energy of three Korean numbers produced by ten female students from narrow-band spectrograms at 19 proportional time points of each voiced segment. Then, cells of the first five spectral matrices were averaged to form a matrix model for each speaker. The correlation coefficients and sum of the absolute amplitude difference in each pair of the spectral models of the ten subjects were obtained. Also, some individual matrix models were compared to those of the same subject or the other subject with a similar spectral model. Results showed that in numbers '2' and '9' subjects could not be clearly distinguished from the others but in number '4' it shed some possibility of setting threshold values for speaker identification if we employed the coefficients and the sum of absolute difference. Further studies would be desirable on various combinations of the range of long-term average spectra and the degree of signal pre-emphasis.

• International Journal of Highway Engineering
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• v.16 no.5
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• pp.165-171
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• 2014

PURPOSES : The objective of this study is to find Percentile Speed($V_p$) for Appraisal of Road Section with Recurring Congestion. METHODS : Percentile Speed($V_p$) is determined by correlation analysis of CSI that proposed existing literature. and CSI(Consistency Service Index) is a index that subtract service fail frequency from 100 points, and service fail is defined as traffic situation is driving less than 80kph speed. In this study, We analyzed the highest correlation percentile speed associated with CSI. This speed is chosen as a delay decision speed. In order to verifying reliability, it performed a comparison with the previous method. RESULTS : As a result, 30 percentile speed($V_{30}$) was decided as index speed for judgement of recurring congestion section, and through comparison with existing methods, we demonstrated that 30 percentile speed can be useful for judgement of recurring congestion section. CONCLUSIONS : This method to Determine recurring congestion section using the percentile speed($V_{30}$) was proposed for the first time in this paper. This method can be applicated more quickly and easily than existing method for determining of recurring delay section.

• Journal of Environmental Health Sciences
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• v.10 no.1
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• pp.1-12
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• 1984

The stochastic characteristics of the daily range of water temperature variation was analyzed by employing the techniques of autocorrelation coefficient, autoreggresive model and crosscorrelation model. These time series included daily observations on maximum and minimum values of water temperature and air temperature. The measurement was made by automatic recording instrument at Gu-yee and Dook-do in Han River, and at Waegwan and Gu-mi in Nackdong River in 1981. As a result of this study, it was found that (1) The correlogram of daily water temperature ranges $\Delta AT_i$ and daily air temperature $\Delta AT_i$ at Gu-mi and Gu-yee showed the exponential curves. (2) The most high frequency values of $\Delta AT_i$ and $\Delta WT_i$ were 11$\circ$C and 0.5${\circ}C$ respectively at every measuring site. (3) The correlation coefficients between the daily mean air temperature AT$_i$ and the daily mean water temperature were fairly high as 0.966 at Dook-do and 0.949 at Gu-yee, but the correlation coefficients between $\Delta AT_i$ and $\Delta WT_i$ were very low as 0.1074 at Gu-yee and 0.0324 at Dook-Do.

• Korean Journal of Rural Living Science
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• v.10 no.2
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• pp.37-51
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• 1999

The objectives of this study were to understand the working stress of rural women and their coping strategies, and to provide basic data related with rural welfare policy. The data were obtained through 318 samples of rural women under sixty years old who work full-time at their farms with their husbands. The questionnaire employed Likert-type scale with four-point, and then the data were analyzed by statistical methods of frequency, percentage, mean score, analysis of variance, t-test and Duncan test through SAS program. The significance level was p ＜ .05. The results of this study are as follows ; 1) The average stress level of rural women was over 2.9 points out of 4. 2) The stress level showed meaningful correlation with such variables as age, education, perception on economic status, and recognition by their husbands and other family members. The rural women who are over forty years old, below high school, disregarded from their family members were marked high stress level. 3) The level of rural women's stress coping strategies was quite as low as 1.95 out of 4. 4) The level of coping strategies showed meaningful correlation with such socio-demographic variables as age, perception on economic status and job satisfaction level. Those who aged over 40, perceives low economic staus, lives together with husbands'parents, and shows “average” job satisfaction scored significantly lower coping strategy levels. 5) The level of stress didn't indicate significant relation with the type of coping strategy.

• Journal of Families and Better Life
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• v.17 no.1
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• pp.45-56
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• 1999

The purpose of this study was to look into correlations between subjective evaluation on the work and self-esteem of the elderly so as to provide information for finding out ways of developing their self-esteem. The subjects of this study were 318 elderly persons in Chonnam and Kwangju city. The statistics used for data analysis were frequency percentage mean standard deviation reliability stepwise and multiple regression analysis through the SAS package program. the major findings of this study can be summarized as follows; 1) The self-esteem of elderly persons was 25,9 which was above the median 24. 2) According to the results related to subjective evaluations on the work among the elderly the positive correlation was by education level family situation economic state social activity level and health state while the negative correlation was by sex, age, and spouse. 3) According to the results related to subjective evaluations on the work among the elderly the positive correl tion was by worker identity job satisfaction quality of work time. 4) In model 1. variable affecting their self-esteem were health sate education level economic state health state age social activity level and sex. In Model 2, variables affecting their self-esteem were worker identity education level economic state age health state social activity level job satisfaction and sex. Especially self-estee of elderly was highly correlated with subjective evaluations on the work among the elderly persons.

• Journal of Korean Academy of Rural Health Nursing
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• v.3 no.1
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• pp.44-52
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• 2008

Purpose: This research was done to analyze factors influencing satisfaction level with welfare services by elderly people living in a mixed urban and rural area and to identify directions for improvement of service by examining characteristics of the recipients, type and content of services and the correlation between the level of satisfaction and related factors. Method: The 102 elderly people receiving services from 4 institutions in a mixed urban and rural area were selected. The results of the research include the following. Results: First general characteristics of the service-recipients, and the actual condition of the service; Second, correlation between satisfaction level of the recipients and their economic condition, health condition and activities of daily living; Third, analysis of level of satisfaction related to type of services, frequency, time required, desire of the recipients and their attitudes; Fourth, satisfaction and related factors were identified and used to identify possible problems and directions to improve service. Conclusion: The results suggest the following as ways to improve service and to increase the level of satisfaction 1) Individualization of services 2) Improvement in the way of selecting recipients 3) Reinforcement of special training courses for service providers.

• Journal of Hospice and Palliative Care
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• v.23 no.4
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• pp.172-182
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• 2020

Purpose: This study aimed to identify the relationships among attitudes towards death, perceptions of hospice care, and hospice care needs as perceived by family members of patients in the intensive care unit (ICU). Methods: This study used a descriptive correlational method. A structured questionnaire was used to collect data from 114 participating families in the ICU at Dong-A University Hospital, from October 10 to November 1, 2019. The data were analyzed in terms of frequency, percentage, and mean and standard deviation. The t-test, one-way analysis of variance, and Pearson correlation coefficients were also conducted. Results: Perceptions of hospice care showed significant differences according to age (F=3.06, P=0.031) and marital status (t=3.55, P=0.001). However, no significant differences in attitudes towards death or hospice care needs were found. A significant positive correlation was found between perceptions of hospice care and hospice care needs (r=0.49, P<0.001). Conclusion: In order for families to recognize the need for hospice care and to receive high-quality palliative care at the appropriate time, it is necessary to increase public awareness of hospice care through various educational and awareness-raising efforts, thereby providing opportunities for families of terminally ill patients to request hospice care.

• Investigative Magnetic Resonance Imaging
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• v.3 no.2
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• pp.159-166
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• 1999

Purpose : To evaluate the effect of rotational correlation time (${\tau}_R$) and the possible related changes of other parameters, ${\tau}_M,{\;}{\tau}_S,{\;}and{\;}(\tau}_V$ of gadolinium (Gd) chelate on T1 relaxation enhancement in two pool model. Materials and Methods : The NMRD (Nuclear Magnetic Relaxation Dispersion) profiles were simulated from 0.02 MHz to 800 MHz proton Larmor frequency for different values of rotational correlation times based on Solomon-Bloembergen equation for inner-sphere relaxation enhancement. To include both unbound pool (pool A) and bound pool (pool B), the relaxivity was divided by contribution from unbound pool and bound pool. The rotational correlation time for pool A was fixed at the value of 0.1 ns, which is a typical value for low molecular weight complexes such as Gd-DTPA in solution and ${\tau}_R$ for pool B was changed from 0.1 ns to 20 ns to allow the slower rotation by binding to macromolecule. The fractional factor of was also adjusted from 0 to 1.0 to simulate different binding ratios to macromolecule. Since the binding of Gd-chelate to macromolecule cab alter the electronic environment of Gd ion and also the degree of bulk water access to hydration site of Gd-chelate, the effects of these parameters were also included. Results : The result shows that low field profiles, ranged from 0.02 to 40 MHz, and dominated by contribution from bound pool, which is bound to macromolecule regardless of binding ratios. In addition, as more Gd-chelate bound to macromolecule, sharp increase of relaxivity at higher field occurs. The NMRD profiles for different values of ${\tau}_S$ show the enormous increase of low field profile whereas relaxivity at high field is not affected by ${\tau}_S$. On the other hand, the change in ${\tau}$V does not affect low field profile but strongly in fluences on both inflection fie이 and the maximum relaxivity value. The results shows a fluences on both inflection field and the maximum relaxivity value. The results shows a parabolic dependence of relaxivity on ${\tau}_M$. Conclusion : Binding of Gd-chelate to a macromolecule causes slower rotational tumbling of Gd-chelate and would result in relaxation enhancement, especially in clinical imaging field. However, binding to macromolecule can change water enchange rate (${\tau}_M$) and electronic relaxation ($T_le$) vis structural deformation of electron environment and the access of bulk water to hydration site of metal-chelate. The clinical utilities of Gd-chelate bound to macromolecule are the less dose requirement, the tissue specificity, and the better perfusion and intravascular agents.

• Korean Journal of Adult Nursing
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• v.21 no.6
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• pp.678-690
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• 2009

Purpose: This study was performed to identify skin health status and the factors influencing skin hydration in the institutionalized elderly. Methods: The subjects were 139 elders living in 2 nursing homes in Seoul. Data for skin health status were collected by measurement of skin hydration, sebum, trans-epidermal water loss and pH using Corneometer, Sebumeter, Tewameter and Skin pH-meter on face, flank, arm and leg. Baseline data were collected by a structured questionnaire. The data were analyzed by SPSS/WIN 12.0 program. Results: Skin hydration and pH were relatively low especially on arms and legs but sebum and TEWL were not low, relatively. There were significant differences in skin health status according to gender, smoking, alcohol intake, and bath cleanser. There was significant positive correlation between skin-hydration and bath-time, TEWL and bath-frequency. Smoking, bath-cleanser, bath-time. pH and gender were identified as the significant influencing factors of skin hydration. Conclusion: Smoking, bath-time and pH need to be considered as important control factors for increasing skin health status in the institutionalized elderly.