Jaesoo Yoo

Roseovarius halotolerans sp. nov., isolated from deep seawater.

A Gram-reaction-negative, non-motile, aerobic bacterium, designated HJ50(T), was isolated from deep seawater of the East Sea, South Korea. Cells were ovoid to rod-shaped (0.5-0.8x1.3-3.0 mum), often with unequal ends, suggesting a budding mode of reproduction. The strain had an absolute requirement for sea salts and tolerated up to 20 % (w/v) sea salts. Propionate, dl-lactate, 2-ketogluconate, 3-hydroxybutyrate and rhamnose were used as growth substrates, but not mannitol, salicin, 4-hydroxybenzoate or acetate. The major fatty acid was summed feature 7 (C(18 : 1)omega7c/omega9t/omega12t) and the DNA G+C content was 59.0+/-0.1 mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that this strain was affiliated with the genus Roseovarius. Similarities between the 16S rRNA gene sequence of strain HJ50(T) (1430 nt) and those of type strains of members of the genus Roseovarius were 94.1-96.3 %. DNA-DNA relatedness values between strain HJ50(T) and the type strains of members of the genus Roseovarius were low (1.3-24.6 %). Physiological and biochemical differences support assignment of strain HJ50(T) to the genus Roseovarius as a representative of a novel species. The name Roseovarius halotolerans sp. nov. is proposed, with HJ50(T) (=KCTC 22224(T) =LMG 24468(T)) as the type strain.

Flavobacterium chungbukense sp. nov., isolated from soil

A yellow-pigmented, Gram-staining-negative, non-motile, strictly aerobic and rod-shaped bacterium, designated CS100(T), was isolated from soil in Chungbuk, Korea. Phylogenetic analysis and comparative studies based on the 16S rRNA gene sequence showed that strain CS100(T) belonged to the genus Flavobacterium in the family Flavobacteriaceae. Strain CS100(T) showed the highest sequence similarities to Flavobacterium glaciei JCM 13953(T) (97.6 %) and Flavobacterium johnsoniae KACC 11410(T) (97.1 %). Sequence similarity to other members of the genus Flavobacterium was 91.5-97.0 %. Growth occurred at 4-30 °C, at pH 5.0-9.0 and in the presence of 0-2 % (w/v) NaCl. Flexirubin-type pigments were produced. Menaquinone-6 (MK-6) was the major respiratory quinone and the major fatty acids were iso-C(15 : 0) (17.3 %), summed feature 3 (comprising iso-C(15 : 0) 2-OH and/or C(16 : 1)ω7c, 15.5 %) and C(16 : 0) (11.8 %). The DNA G+C content was 36.4 mol%. Strain CS100(T) hydrolysed skimmed milk and gelatin, but not chitin or pectin, and showed oxidase and catalase activities. DNA-DNA relatedness was 3.0 % with F. glaciei JCM 13953(T) and 11.5 % with F. johnsoniae KACC 11410(T). On the basis of the evidence from this study, strain CS100(T) represents a novel species of the genus Flavobacterium, for which the name Flavobacterium chungbukense sp. nov. is proposed. The type strain is CS100(T) ( = KACC 15048(T) = JCM 17386(T)).

Data Correlation-Based Clustering Algorithm in Wireless Sensor Networks

Many types of sensor data exhibit strong correlation in both space and time. Both temporal and spatial suppressions provide opportunities for reducing the energy cost of sensor data collection. Unfortunately, existing clustering algorithms are difficult to utilize the spatial or temporal opportunities, because they just organize clusters based on the distribution of sensor nodes or the network topology but not on the correlation of sensor data. In this paper, we propose a novel clustering algorithm based on the correlation of sensor data. We modify the advertisement sub-phase and TDMA schedule scheme to organize clusters by adjacent sensor nodes which have similar readings. Also, we propose a spatio-temporal suppression scheme for our clustering algorithm. In order to show the superiority of our clustering algorithm, we compare it with the existing suppression algorithms in terms of the lifetime of the sensor network and the size of data which have been collected in the base station. As a result, our experimental results show that the size of data is reduced and the whole network lifetime is prolonged.

Development of a digital textbook standard format based on XML

This paper proposes a standard format for those digital textbooks which are used in Korean elementary and secondary school. This standard format comprises an array of function and XML-based document formats. The format aims to maximize the effectiveness of learning by combining the usual advantages of printed textbooks and the additional functions of digital media such as searching and navigation, audiovisuals, animations, 3D graphics and other state-of-the-art multimedia functions. Another objective is to facilitate the interoperability of digital textbooks among different users and service providers by developing an XML-based document format.

Pseudoalteromonas donghaensis sp. nov., isolated from seawater

A Gram-negative, rod-shaped, motile and aerobic bacterium, designated strain HJ51(T), was isolated from a seawater sample from the East Sea, near South Korea. The isolate grew slowly at 4 °C, was able to grow at 40 °C, required NaCl and grew optimally at pH 6.5-7.0. The G+C content of the genomic DNA was 41.8 mol%. The major fatty acids were summed feature 4 (C(16 : 1)ω7c and/or iso-C(15 : 0) 2-OH), C(16 : 0) and summed feature 7 (C(18 : 1)ω7c, C(18 : 1)ω9t and/or C(18 : 1)ω12t). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain HJ51(T) belonged to the genus Pseudoalteromonas and had 91.7-98.9 % 16S rRNA gene sequence similarity with type strains of species of the genus Pseudoalteromonas. Strain HJ51(T) had 7.2 % DNA-DNA relatedness with Pseudoalteromonas mariniglutinosa DSM 15203(T) and 12.9 % with Pseudoalteromonas prydzensis DSM 14232(T). On the basis of the phenotypic, phylogenetic and genomic data, strain HJ51(T) represents a novel species of the genus Pseudoalteromonas, for which the name Pseudoalteromonas donghaensis sp. nov. is proposed. The type strain is HJ51(T) (=KCTC 22219(T)=LMG 24469(T)).

An efficient data-centric storage method using time parameter for sensor networks

In wireless sensor networks, various schemes have been proposed to efficiently store and process sensed data. Among them, the data-centric storage (DCS) scheme is one of the most well-known. The DCS scheme distributes data regions and stores the data in the sensor that is responsible for the region. The DCS based scheme was proposed to reduce the communication cost for transmitting data and to efficiently process exact queries and range queries. Recently, a KDDCS scheme was proposed to overcome storage hot-spots by dynamically readjusting the distributed data regions to sensors based on the K-D tree. However, the existing DCS based schemes including KDDCS suffer from query hot-spots that are formed when query regions are not uniformly distributed. As a result, it reduces the lifetime of the sensor network.In this paper, we propose a new DCS based scheme, called Time-Parameterized Data-Centric Storage (TPDCS), that avoids the problems of storage hot-spots and query hot-spots. To decentralize the skewed data and queries, the data regions are assigned by a time dimension as well as data dimensions in our proposed scheme. Therefore, TPDCS extends the lifetime of sensor networks. It is shown through various experiments that our scheme outperforms the existing schemes.

An Efficient Data Dissemination Method over Wireless Ad-Hoc Networks

Recently, mobile data is increased sharply with the rapid development of mobile devices such as smart phone, tablet, and pocket computer. Due to mobile devices are becoming more ubiquitous and most of the mobile devices are equipped with short range wireless communication technologies, the research on data dissemination over mobile devices based mobile ad-hoc networks becomes increasingly popular. Because most of the previous data dissemination methods over mobile ad-hoc networks did not consider user preferences, they resulted in a lot of unnecessary data transmissions in the network. Although some recent studies investigated the importance of satisfying user preference during data dissemination over mobile ad-hoc networks, they either required high network management overhead or could not guarantee that the data packets can be disseminated to all of the mobile nodes that are interested in the data. In this paper, we propose an efficient method which leverages user interests and location information to support data dissemination in wireless ad hoc networks. We propose two relay nodes selection method to filter out unnecessary data transmissions in the network, such as passive relay nodes selection method and active relay nodes selection method. Compared with existing methods, the proposed data dissemination method reduces a lot of unnecessary data transmissions without requiring high network management overhead. The experimental results show that the proposed method outperforms the existing methods.

Utilization of Social Media Analysis using Big Data

The analysis method using Big Data has evolved based on the Big data Management Technology. There are quite a few researching institutions anticipating new era in data analysis using Big Data and IT vendors has been sided with them launching standardized technologies for Big Data management technologies. Big Data is also affected by improvements of IT gadgets IT environment. Foreran by social media, analyzing method of unstructured data is being developed focusing on diversity of analyzing method, anticipation and optimization. In the past, data analyzing methods were confined to the optimization of structured data through data mining, OLAP, statics analysis. This data analysis was solely used for decision making for Chief Officers. In the new era of data analysis, however, are evolutions in various aspects of technologies; the diversity in analyzing method using new paradigm and the new data analysis experts and so forth. In addition, new patterns of data analysis will be found with the development of high performance computing environment and Big Data management techniques. Accordingly, this paper is dedicated to define the possible analyzing method of social media using Big Data. this paper is proposed practical use analysis for social media analysis through data mining analysis methodology.

Disjointed Multipath Routing for Real-Time Data in Wireless Multimedia Sensor Networks

Wireless multimedia sensor networks with sensing and processing abilities of multimedia data have recently emerged as one of the most important technologies for high quality monitoring. The routing scheme for multimedia data is an important research issue addressed in wireless multimedia sensor networks. In this paper, we propose a disjointed multipath routing scheme for real-time data transmission in wireless multimedia sensor networks. The proposed scheme uses a hybrid routing protocol based on Bluetooth and Zigbee in order to overcome the limitation of low bandwidth in conventional sensor networks. The proposed scheme also performs disjointed multipath routing based on competition to alleviate the delay of routing path setup. To show the superiority of our proposed scheme, we compare it with the existing scheme through performance evaluation. Our experimental results show that our proposed scheme reduces the end-to-end delay by about 30% and the routing path setup costs by about 22% over the existing scheme. Our scheme also increases data reception rates by about 690% over the existing scheme on average.

Data-aware top-k monitoring in wireless sensor networks

Top-k queries are important to many wireless sensor applications. Conventional Top-k query processing algorithms install a filter at each sensor node and suppress unnecessary sensor updates. However, they have some drawbacks that the sensor nodes consume energy extremely to probe sensor reading or update filters. Especially, it becomes worse, when the variation ratio of top-k result is higher. In this paper, we propose a novel top-k query processing algorithm for energy-efficiency. First, each sensor determines its priority as the order of data gathering. Next, sensor nodes that have higher priority transmit their sensor readings to the base station until gathering k sensor readings. In order to show the superiority of our query processing algorithm, we simulate the performance with the existing query processing algorithms. As a result, our experimental results show that the network lifetime of our method is prolonged largely over the existing method.