• 한국멀티미디어학회논문지
• /
• 제24권6호
• /
• pp.768-788
• /
• 2021

The reversible data hiding technique safely transmits secret data to the recipient from malicious attacks by third parties. In addition, this technique can completely restore the image used as a transmission medium for secret data. The reversible data hiding schemes have been proposed in various forms, and recently, the reversible data hiding schemes based on interpolation are actively researching. The reversible data hiding scheme based on the interpolation method expands the original image into the cover image and embed secret data. However, the existing interpolation-based reversible data hiding schemes did not embed secret data during the interpolation process. To improve this problem, this paper proposes embedding the first secret data during the image interpolation process and embedding the second secret data into the interpolated cover image. In the embedding process, the original image is divided into blocks without duplicates, and the maximum and minimum values are determined within each block. Three way searching based on the maximum value and two way searching based on the minimum value are performed. And, image interpolation is performed while embedding the first secret data using the PVD scheme. A stego image is created by embedding the second secret data using the maximum difference value and log function in the interpolated cover image. As a result, the proposed scheme embeds secret data twice. In particular, it is possible to embed secret data even during the interpolation process of an image that did not previously embed secret data. Experimental results show that the proposed scheme can transmit more secret data to the receiver while maintaining the image quality similar to other interpolation-based reversible data hiding schemes.

• 대기
• /
• 제26권3호
• /
• pp.483-492
• /
• 2016

We have examined the random error of eddy covariance (EC) measurements on the basis of two-tower approach during daytime. Two EC towers were placed on the grassland with different vegetation density near Gumi-weir. We calculated the random error using three different methods. The first method (M1) is two-tower method suggested by Hollinger and Richardson (2005) where random error is based on differences between simultaneous flux measurements from two towers in very similar environmental conditions. The second one (M2) is suggested by Kessomkiat et al. (2013), which is extended procedure to estimate random error of EC data for two towers in more heterogeneous environmental conditions. They removed systematic flux difference due to the energy balance deficit and evaporative fraction difference between two sites before determining the random error of fluxes using M1 method. Here, we introduce the third method (M3) where we additionally removed systematic flux difference due to available energy difference between two sites. Compared to M1 and M2 methods, application of M3 method results in more symmetric random error distribution. The magnitude of estimated random error is smallest when using M3 method because application of M3 method results in the least systematic flux difference between two sites among three methods. An empirical formula of random error is developed as a function of flux magnitude, wind speed and measurement height for use in single tower sites near Nakdong River. This study suggests that correcting available energy difference between two sites is also required for calculating the random error of EC data from two towers at heterogeneous site where vegetation density is low.

• Smart Structures and Systems
• /
• 제25권5호
• /
• pp.593-604
• /
• 2020

Temperature may have more significant influences on structural responses than operational loads or structural damage. Therefore, a comprehensive understanding of temperature distributions has great significance for proper design and maintenance of bridges. In this study, the temperature distribution of the steel box girder is systematically investigated based on the structural health monitoring system (SHMS) of the Sutong Cable-stayed Bridge. Specifically, the characteristics of the temperature and temperature difference between different measurement points are studied based on field temperature measurements. Accordingly, the probability density distributions of the temperature and temperature difference are calculated statistically, which are further described by the general formulas. The results indicate that: (1) the temperature and temperature difference exhibit distinct seasonal characteristics and strong periodicity, and the temperature and temperature difference among different measurement points are strongly correlated, respectively; (2) the probability density of the temperature difference distribution presents strong non-Gaussian characteristics; (3) the probability density function of temperature can be described by the weighted sum of four Normal distributions. Meanwhile, the temperature difference can be described by the weighted sum of Weibull distribution and Normal distribution.

• 사상체질의학회지
• /
• 제27권2호
• /
• pp.288-296
• /
• 2015

Objectives Purpose of this study was to examine difference of taste score in herbal medicine among Sasang Constitution groups. Methods Seventy-three healthy students tasted salt solution, sucrose solution, four herbal medications (Hyangsayangwi-tang, Yanggyeoksanhwa-tang, Yeoldahanso-tang, and Mihudeungsikjang-tang), and then immediately scored intension of stimuli for each taste which they felt. Data of sixty-four final participant were analyzed by SPSS version 18, as follows: frequency analysis for characteristic data of participants, Kruskal-wallis test for difference in taste score among Sasang Constitution groups, and Pearson correlation analysis for the correlation between taste score of single taste stimuli and taste scores of herbal medications. Results Significant difference was shown in sweet taste score of Hyangsayangwi-tang among Sasang Constitution groups, that Soyangin showed higher sweet taste score of Hyangsayangwi-tang than Soeumin's. No significant difference was shown in other tastes or other herbal medications. Positive correlation between taste score of sucrose solution and sweet taste score of herbal medication was shown in Soemin. Conclusions There is difference in sweet taste score of Hyangsayangwi-tang among Sasang Constitution groups. There is positive correlation between sweet taste score of sucrose solution and herbal medication. This research has limitation, so well-designed research is needed.

• 전기학회논문지
• /
• 제58권1호
• /
• pp.173-180
• /
• 2009

It is difficult to predict non-stationary or chaotic time series which includes the drift and/or the non-linearity as well as uncertainty. To solve it, we propose an effective prediction method which adopts data preprocessing and multiple model TS fuzzy predictors combined with model selection mechanism. In data preprocessing procedure, the candidates of the optimal difference interval are determined based on the correlation analysis, and corresponding difference data sets are generated in order to use them as predictor input instead of the original ones because the difference data can stabilize the statistical characteristics of those time series and better reveals their implicit properties. Then, TS fuzzy predictors are constructed for multiple model bank, where k-means clustering algorithm is used for fuzzy partition of input space, and the least squares method is applied to parameter identification of fuzzy rules. Among the predictors in the model bank, the one which best minimizes the performance index is selected, and it is used for prediction thereafter. Finally, the error compensation procedure based on correlation analysis is added to improve the prediction accuracy. Some computer simulations are performed to verify the effectiveness of the proposed method.

• 한국농공학회논문집
• /
• 제59권6호
• /
• pp.73-80
• /
• 2017

The objective of this study is to investigate whether the daily rainfall depth derived from daily data represents the event rainfall depth derived from hourly data. For analysis, the 85th, 90th, and 95th percentile daily rainfall depths were first computed using daily rainfall data (1986~2015) collected at 63 weather stations. In addition, the storm event was separated by the interevent time definition (IETD) of 6, 12, 18, and 24 hr using hourly rainfall data. Based on the separated storm events, the 85th, 90th, and 95th percentile event rainfall depths were calculated and compared with the using hourly rainfall data with the 85th, 90th, and 95th percentile daily rainfall depths. The event rainfall depths computed using the IETD were greater than the daily rainfall depths. The difference between the event rainfall depth and the daily rainfall depth affects the design and size of the facility for controlling the stormwater. Therefore, the designer and policy decision-maker in designing the stormwater best management practices need to take into account the difference generated by the difference of the used rainfall data and the selected IETD.

• 산업공학
• /
• 제19권1호
• /
• pp.86-96
• /
• 2006

Some customer data of manufacturing industries have a large number of incomplete data set due to the customer's infrequent purchasing behavior and the limitation of customer profile data gathered from sales representatives. So that, most sophisticated data analysis methods may not be applied directly. This paper proposes a heuristic data analysis method to classify customers in household appliances industries. The proposed PD (percent of difference) method can be used for the discriminant analysis of incomplete customer data with simple mathematical calculations. The method is composed of variable distribution estimation step, PD measure and cluster score evaluation steps, variable impact construction step, and segment assignment step. A real example is also presented.

• 한국실내디자인학회논문집
• /
• 제20권5호
• /
• pp.143-151
• /
• 2011

Since it is important to understand data acquiring characteristics through relationship between spatial types and spatial elements and apply it to spatial plans for smooth communication between designer and user of space, the conclusions gained from analysis of data acquiring characteristics of spatial elements through image evaluation by types of interior space can be summarized as in the followings: First, for the amount of acquired data by types of interior space, it shows that the acquired amount of data is to change by types and data acquiring method (phrase and image) even though the spatial elements are same. Second, for the data acquiring process of spatial types by gender, it shows that there is a big difference in acquiring of data according to the evaluation method by phrase and image. Third, for the amount of acquired data of spatial types by gender, it shows that there is a difference between male and female, which is by "classic ${\rightarrow}$ modern ${\rightarrow}$ natural" in case of male and "classic ${\rightarrow}$ natural ${\rightarrow}$ modern" in case of female. regarding both of phrase and image. Fourth, for the evaluation by gender, it shows that there is a deviation in the value of difference according to the elements by which data acquiring characteristics evaluate space. It is considered that this deviation characteristic is in need of reflection in the process of spatial evaluation. This study analyzed data acquiring characteristics of space user's spatial elements through image evaluation by types of space to understand how data acquiring would be changed of spatial elements according to type and gender. Through this study, it expects to make clear that, when a designer is planning a certain space, if the space can be a space for the user by understanding of which elements should be exposed to users by types to acquire more data.

• 복식문화연구
• /
• 제19권1호
• /
• pp.1-18
• /
• 2011

The purpose of this study is to prepare the base for the development of the high value clothing products with eco-friendly fabric which become the conversation topic recently. In order to collect data, a questionnaire was used. The subject of survey was the adult women in from their 20's to 50's. The survey areas were Gyungnam, Busan, Ulsan, and Daegu in Korea. The questions were formed with the results of a preliminary investigation and the contents selectively revised the measurement tools used to the previous studies. To analyze the collected data, $x^2$2-test, t-test, ANOVA were carried out with SPSS. In the result of difference analysis of the actual purchase conditions according to demographic variables, the purchase motives, the purchase items, and the purchase information showed the significant difference according to the demographic variables except monthly income, and the purchase place showed the significant difference to all the demographic variables. The results of difference analysis of post-purchase satisfaction according to the demographic variables and the purchase items were as follows, The post-purchase satisfaction in price showed the significant difference according to age and monthly income. The one in design showed the significant difference according to educational level and occupation. The one in fashion showed the significant difference according to marriage or non-marriage, age, educational level and occupation. The one in the wearing sensation showed the significant difference according to marriage or nonmarriage, age, educational level, occupation. The one in transformation showed the significant difference according to educational level, monthly income, purchase item. The one in laundry and management convenience showed the significant difference according to monthly income and purchase item. Finally, the one in pollution level showed the significant difference according to age, monthly income, occupation, and purchase item.

• 대한의용생체공학회:의공학회지
• /
• 제16권3호
• /
• pp.271-278
• /
• 1995

An ECG data compression algorithM using max-min slope update is proposed and a real time 3 channel ECG transmission system is implemented using the proposed algorithm. In order to effectively compress ECG data, we compare a threshold value with the max-min slope difference (MMSD) which is updated at each sample values. If this MMSD value is smaller than the threshold value, then the data is compressed. Conversely, when the MMSD value is larger than threshold value, the data is transmitted after storing the value and the length between the data which is beyond previous threshold level. As a result, it can accurately compress both the region of QRS, P, and T wave that has fast-changing and the region of the base line that slope is changing slow. Therefore, it Is possible to enhance the compression rate and the percent roms difference. In addition, because of the simplicity, this algorithm is more suitable for real-time implementation.