• Journal of KIISE
• /
• v.42 no.1
• /
• pp.97-106
• /
• 2015

Recently, research on database encryption for data protection and query result authentication methods has been performed more actively in the database outsourcing environment. Existing database encryption schemes are vulnerable to order matching and counting attack of intruders who have background knowledge of the original database domain. Existing query result integrity auditing methods suffer from the transmission overhead of verification object. To resolve these problems, we propose a group-order preserving encryption index and a query result authentication method based on the encryption index. Our group-order preserving encryption index groups the original data for data encryption and support query processing without data decryption. We generate group ids by using the Hilbert-curve so that we can protect the group information while processing a query. Finally, our periodic function based data grouping and query result authentication scheme can reduce the data size of the query result verification. Through performance evaluation, we show that our method achieves better performance than an existing bucket-based verification scheme, it is 1.6 times faster in terms of query processing time and produces verification data that is 20 times smaller.

• Journal of KIISE:Information Networking
• /
• v.37 no.1
• /
• pp.1-7
• /
• 2010

Network Centric Warfare(NCW) is becoming a prominent concept in the current trend of warfare. To support high quality communication between strategic/tactical units in the concept of NCW, Tactical Airborne Networks are likely to be constructed in the near future to take part in the NCW. In these Tactical Airborne Networks with dynamic topology variations due to very high mobility of participants nodes, more efficient and reliable neighbor discovery protocols are needed. This paper presents the adaptive HELLO message scheduling algorithm for Tactical Airborne Network using directional antennas. The purposed algorithm can reduce the overhead of periodic HELLO message transfer, while guaranteeing successful data transmission. We concluded a mathematical analysis and simulation studies using Qualnet 4.5 for evaluation the performance and efficiency of the proposed scheme.

• Korean Journal of Veterinary Research
• /
• v.37 no.1
• /
• pp.25-39
• /
• 1997

The morphology of the ductuli efferentes of the Korean native pheasants were observed in order to obtain a basic data for further studying reproductive physiology and other male genital organs. The mature (14-16 months after hatching) male pheasants were used in this study. The specimens from pheasants were collected on a monthly basis. The general morphological changes of the ductuli efferentes were observed with hematoxylineosin stain, and semithin section by light microscope. The ultrastructural changes of the ductuli efferentes were investigated with ultrathin section by transmission electron microscope. The results obtained are summarized as follows : 1. During the breeding season, the average height of ductuli efferentes epithelium was $23.45{\pm}2.34{\mu}m$ and was largely decreased by $17.85{\pm}2.01{\mu}m$ during the non-breeding season. The thickeness of interstitial tissue was comparatively increased during the non-breeding season. 2. During the breeding season, the epithelial cells of ductuli efferentes were well developed. During the non-breeding season, epithelial layer and lumen of ductuli efferentes, were markedley reduced compared with those of breeding season. 3. Morphological changes of the ductuli efferentes underwent periodic changes paralleling to the spermatogenic cycle. 4. At least two different cell types were identified in the epithelium of ductuli efferentes, namely non-ciliated and ciliated cells. 5. The ciliated cells possess many vesicles, slightly smaller than those of the non-ciliated cells. 6. The ciliated cells contained numerous mitochondria, smooth and rough endoplasmic reticulum, Golgi complex, lysosome, and oval nuclei. The non-ciliated cells had a irregular nuclei and a cytoplasm containing few organelles. 7. During the breeding season, a number of vesicles, rough and smooth endoplasmic reticulum, Golgi complex, and mitochondria were distinctively showed in the epithelial cells but in the non-breeding season only a few observed.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.26 no.7
• /
• pp.1026-1031
• /
• 2022

Cognitive Radio Ad-Hoc Networks (CRAHNs) enable to overcome the shortage of frequency resources due to the increase of radio services. In order to avoid interference with the primary user in CRANH, channel sensing to check the idle channel is required, and when the primary user appears, the time delay due to handover should be minimized through fast idle channel selection. In this paper, throughput was improved by reducing the number of channel sensing and preferentially sensing a channel with a high probability of being idle, using reinforcement learning. In addition, we proposed a multi-channel MAC (Medium Access Control) protocol that can minimize the possibility of collision with the primary user by sensing the channel at the time of data transmission without performing periodic sensing. The performance was compared and analyzed through computer simulation.

• Journal of Veterinary Clinics
• /
• v.33 no.2
• /
• pp.107-112
• /
• 2016

The objective of this study was to determine potential contributing factors associated with biosecurity level of farrow-to-finish pig farms and to develop a classification tree model to explore how these factors related to each other based on prediction model. To this end, the author analyzed data (n = 193) extracted from a cross-sectional study of 344 farrow-to-finish farms which was conducted between March and September 2014 aimed to explore swine disease status at farm level. Standardized questionnaires with information about basic demographical data and management practices were collected in each farm by on-site visit of trained veterinarians. For the classification of the data sets regarding biosecurity level as a dependent variable and predictor variables, Chi-squared Automatic Interaction Detection (CHAID) algorithm was applied for modeling classification tree. The statistics of misclassification risk was used to evaluate the fitness of the model in terms of prediction results. Categorical multivariate input data (40 variables) was used to construct a classification tree, and the target variable was biosecurity level dichotomized into low versus high. In general, the level of biosecurity was lower in the majority of farms studied, mainly due to the limited implementation of on-farm basic biosecurity measures aimed at controlling the potential introduction and transmission of swine diseases. The CHAID model illustrated the relative importance of significant predictors in explaining the level of biosecurity; maintenance of medical records of treatment and vaccination, use of dedicated clothing to enter the farm, installing fence surrounding the farm perimeter, and periodic monitoring of the herd using written biosecurity plan in place. The misclassification risk estimate of the prediction model was 0.145 with the standard error of 0.025, indicating that 85.5% of the cases could be classified correctly by using the decision rule based on the current tree. Although CHAID approach could provide detailed information and insight about interactions among factors associated with biosecurity level, further evaluation of potential bias intervened in the course of data collection should be included in future studies. In addition, there is still need to validate findings through the external dataset with larger sample size to improve the external validity of the current model.