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Caching efficiency is critical to performance when an in-memory database system acts as a cache for a disk-oriented database system. Memcached, one of the widely used in-memory database that stores key-values, roles as a cache for high-speed data storage layer. It replaces items using LRU replacement policy when memory capacity is used up. Other than LRU policy for maximizing temporal locality, in this paper, we confirm the impact of replacement policies for workloads with random pattern operations. We analyze hit counts of workload by applying BIP and SRRIP replacement policies to Memcached. Experimental results show that hit counts of Memcached to which SRRIP is applied is improved by up to 12%.

Cell operation in the Near Threshold Voltage (NTV) domain is attracting attention as one of the circuit level low-power implementations circuit. In this domain, cell operation has large delay characteristic compared to Super Threshold Voltage (STV) environment but has high energy efficiency. In order to utilize circuit that operate in Near Threshold Voltage domain, supporting of Computer-Aided Design(CAD) is essential. There are many recently work about design methodology to apply NTV circuit. Although design methodology exploration in the NTV area has been actively studied, it is difficult to immediately commercialize the research at CAD flow due to modified design methodology. In this work, we propose asymmetric slew logic threshold optimization on NTV without modifying CAD flow. Our proposed approach achieves 9.07%, 11.30% and 9.06% improvement in accuracy in stage delay, stage slew and path delay, respectively, compared to the existing symmetric slew logic threshold method.

Picture archiving and communications system (PACS) is widely used in hospitals to bring high efficiency in a medical process. Recently, PACS is required to evolve into a more sophisticated system that can communicate with other medical systems. The existing PACS was designed to be used in a local area network (LAN) of a hospital and DICOM, the standard used in PACS, doesn't have any QoS for file transmission or security functions for an open network. Therefore, we propose a PACS system over Policy Quorum based Resource Management (PQRM) system, which manages storage resources and computing resources in Grid environment to provide satisfying advanced medical services with guaranteed QoS. Finally, we test the real situation medical scenario to prove the advanced functions our system provides and do several experiments to show the superiority of our novel system to existing PACS systems. The results indicate that while PQRM-based PACS providing the ability for advanced medical services it guarantees the transmission, provides best resource selection and disaster recovery capability.

Picture archiving and communications system (PACS) is widely used in hospitals to take medical images, to send images to radiologists or doctors and to store images into storage in a digital manner, that has brought high efficiency in a medical process. Recently, PACS is required to evolve into a more sophisticated system that can communicate with other medical systems. The existing PACS was designed to be used in a Local Area Network (LAN) of a hospital and DICOM, the standard used in PACS, doesn't have any QoS for file transmission or security functions for an open network. Therefore, we propose a PACS system over Policy Quorum based Resource Management (PQRM) system, which manages storage resources and computing resources in Grid environment to provide satisfying advanced medical services with guaranteed QoS. Finally, we test the real situation medical scenario to prove the advanced functions our system provides and do several experiments to show the superiority of our novel system to existing PACS systems. The results indicate that while PQRM-based PACS providing the ability for advanced medical services it guarantees the transmission, provides best resource selection and disaster recovery capability.

Picture archiving and communications system (PACS) is widely used in hospitals to take medical images, to send images to radiologists or doctors and to store images into storage in a digital manner, that has brought high efficiency in a medical process. Recently, PACS is required to evolve into a more sophisticated system that can communicate with other medical systems. The existing PACS was designed to be used in a local area network (LAN) of a hospital and DICOM, the standard used in PACS, doesn't have any QoS for file transmission or security functions for an open network. Therefore, we propose a PACS system over policy quorum based resource management (PQRM) system, which manages storage resources and computing resources in Grid environment to provide satisfying advanced medical services with guaranteed QoS. Finally, we test the real situation medical scenario to prove the advanced functions our system provides and do several experiments to show the superiority of our novel system to existing PACS systems. The results indicate that while PQRM-based PACS providing the ability for advanced medical services it guarantees the transmission, provides best resource selection and disaster recovery capability.

The mission-critical application, in particular e-health service such as ECG application and carotid artery application, normally demands the highly sophisticated handling method and reliable processing scheme in wireless grid environments. Due to the huge amounts of data set from the numerous wireless devices, we propose the refined procedures based on wireless grid to guarantee the optimal processing time and reliability as prime factor of the system performance by using the proposed scheduling scheme. The simulation results show that proposed load scheduling can support the load balancing and guarantee the high system availability.

The imputation of missing values is necessary for the efficient use of DNA microarray data, because many clustering algorithms and some statistical analysis require a complete data set. A few imputation methods for DNA microarray data have been introduced, but the efficiency of the methods was low and the validity of imputed values in these methods had not been fully checked. We developed a new cluster-based imputation method called sequential K-nearest neighbor (SKNN) method. This imputes the missing values sequentially from the gene having least missing values, and uses the imputed values for the later imputation. Although it uses the imputed values, the efficiency of this new method is greatly improved in its accuracy and computational complexity over the conventional KNN-based method and other methods based on maximum likelihood estimation. The performance of SKNN was in particular higher than other imputation methods for the data with high missing rates and large number of experiments. Application of Expectation Maximization (EM) to the SKNN method improved the accuracy, but increased computational time proportional to the number of iterations. The Multiple Imputation (MI) method, which is well known but not applied previously to microarray data, showed a similarly high accuracy as the SKNN method, with slightly higher dependency on the types of data sets. Sequential reuse of imputed data in KNN-based imputation greatly increases the efficiency of imputation. The SKNN method should be practically useful to save the data of some microarray experiments which have high amounts of missing entries. The SKNN method generates reliable imputed values which can be used for further cluster-based analysis of microarray data.