• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.17 no.1
• /
• pp.210-217
• /
• 2013

The development of collaboration among information systems in accordance with changes in enterprises' business environment brings about the problems of duplication of the existing business services and increase in costs of maintenance. Accordingly, Web service has been suggested as the standard of distributed computing to prevent the duplication of services within the same business domain and to attain the services that are already being utilized. But since the data needed for Web services are not standardized, it is difficult for the users to find services that meet diverse business purposes. In this paper, we construct an ontology-based collaboration system for service interoperability. The ontology can support fusion service by finding services which are existed interdependently under the distributed environment for collaboration processing. The role of the collaborative system includes development, registration and call of services based on ontology. A local systems request collaboration support through the service profile. Collaborative system supports the development of service using the service profiles, represents the semantic association between real data through system ontology, and infers relationship between instances contained in the services. Based on this, we applied the travel booking services for collaboration system. As a result, service can be managed effectively preventing collision in collaborative system, and we verify that the mapping between system is reduced.

• Journal of KIISE
• /
• v.42 no.1
• /
• pp.54-67
• /
• 2015

Nowadays, studies on the fusion of Semantic Web technologies are being carried out to promote the interoperability and value of sensor data in an IoT environment. To accomplish this, the semantic translation of sensor data is essential for convergence with service domain knowledge. The existing semantic translation technique, however, involves translating from static metadata into semantic data(RDF), and cannot properly process real-time and large-scale features in an IoT environment. Therefore, in this paper, we propose a technique for translating large-scale streaming sensor data generated in an IoT environment into semantic data, using real-time and parallel processing. In this technique, we define rules for semantic translation and store them in the semantic repository. The sensor data is translated in real-time with parallel processing using these pre-defined rules and an ontology-based semantic model. To improve the performance, we use the Apache Storm, a real-time big data analysis framework for parallel processing. The proposed technique was subjected to performance testing with the AWS observation data of the Meteorological Administration, which are large-scale streaming sensor data for demonstration purposes.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.3
• /
• pp.896-905
• /
• 2010

The sensor networks can be used attractively for various application areas. Time synchronization is important for any Ubiquitous Sensor Networks (USN) systems. USN makes extensive use of synchronized time in many contexts for data fusion. However existing time synchronization protocols are available only for homogeneous sensor nodes of USN. It needs to be extended or redesigned in order to apply to the USN with heterogeneous sensor nodes. Because heterogeneous sensor nodes have different clock sources with the SinkNode of USN, it is impossible to be synchronized global time. In addition, energy efficiency is one of the most significant factors to influence the design of sensor networks, as sensor nodes are limited in power, computational capacity, and memory. In this paper, we propose specific time synchronization based on master-slave topology for the global time synchronization of USN with heterogeneous sensor nodes. The time synchronization master nodes are always able to be synchronized with the SinkNode. Then time synchronization master nodes enable time synchronization slave nodes to be synchronized sleep periods. The proposed master-slave time synchronization for heterogeneous sensor nodes of USN is also helpful for power saving by maintaining maximum sleep time.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.2
• /
• pp.609-615
• /
• 2014

Due to the recent global recession, the car industry demand levels have plummeted which led to a crisis in the automotive parts industry for the first time in history. Since the fourth quarter of 2008, the automotive parts manufacturers in America have faced a record loss and those in Japan and Europe who also had a strong track record are facing a weak economy. In addition, the domestic automotive parts industry is also affected by the global economic crisis. This research is that the relative efficiency analysis utilizing the DEA has done on the object of 25 small and medium-sized automotive parts manufacturers publicly listed, As the efficiency analysis result 6 of 25 manufacturers are efficient in CCR model and 12 manufactures have shown efficiency in BCC model, the efficiency analysis in consideration of the manufacturer size. The manufacturers with efficiency 1 in 25 manufacturers are DMU 1, 5, 7, 10, 18, 24 and the relatively benchmarking objects in other manufactures are DMU 1, 10, 24, Based on the results of this research, a direction to the domestic automotive parts manufacturers as well as a significant information will be provided in managing the companies in the future by the improvement of management efficiency through the practical efficiency analysis.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.19 no.2
• /
• pp.323-335
• /
• 2015

Mobile healthcare is a fusion of information technology and biotechnology and is a new type of health management service to keep people's health at anytime and anywhere without regard to time and space. The WBAN(Wireless Body Area Network) technology that collects bio signals and the data analysis and monitoring technology using mobile devices are essential for serving mobile healthcare. WBAN consisting of users with mobile devices meet another WBAN during movement, WBANs transmit data to the other media. Because of WBAN conflict, several nodes transmit data in same time slot so a collision will occur, resulting in the data transmission being failed and need more energy for re-transmission. In this thesis, we proposed a MAC protocol for WBAN with mobility to solve these problems. First, we proposed a superframe structure for WBAN. The proposed superframe consists of a TDMA(Time Division Muliple Access) based contention access phase with which a node can transmit data in its own time slot and a contention phase using CSMA/CA algorithm. Second, we proposed a network merging algorithm for conflicting WBAN based on the proposed MAC protocol. When a WBAN with mobility conflicts with other WBAN, data frame collision is reduced through network reestablishment. Simulations are performed using a Castalia based on the OMNeT++ network simulation framework to estimate the performance of the proposed superframe and algorithms. We estimated the performance of WBAN based on the proposed MAC protocol by comparing the performance of the WBAN based on IEEE 802.15.6. Performance evaluation results show that the packet transmission success rate and energy efficiency are improved by reducing the probability of collision using the proposed MAC protocol.

• Journal of Chest Surgery
• /
• v.48 no.1
• /
• pp.33-39
• /
• 2015

Background: This study aimed to investigate sternal healing over time and the incidence of poor sternal healing in patients undergoing coronary artery bypass graft (CABG) surgery using bilateral internal thoracic arteries. Methods: This study enrolled 197 patients who underwent isolated CABG using skeletonized bilateral internal thoracic arteries (sBITA) from 2006 through 2009. Postoperative computed tomography (CT) angiography was performed on all patients at monthly intervals for three to six months after surgery. In 108 patients, an additional CT study was performed 24 to 48 months after surgery. The axial CT images were used to score sternal fusion at the manubrium, the upper sternum, and the lower sternum. These scores were added to evaluate overall healing: a score of 0 to 1 reflected poor healing, a score of 2 to 4 was defined as fair healing, and a score of 5 to 6 indicated complete healing. Medical records were also retrospectively reviewed to identify perioperative variables associated with poor early sternal healing. Results: Three to six months after surgery, the average total score of sternal healing was $2.07{\pm}1.52$ and 68 patients (34.5%) showed poor healing. Poor healing was most frequently found in the manubrium, which was scored as zero in 72.6% of patients. In multivariate analysis, the factors associated with poor early healing were shorter post-surgery time, older age, diabetes mellitus, and postoperative renal dysfunction. In later CT images, the average sternal healing score improved to $5.88{\pm}0.38$ and complete healing was observed in 98.2% of patients. Conclusion: Complete sternal healing takes more than three months after a median sternotomy for CABG using sBITA. Healing is most delayed in the manubrium.

• Journal of the Korean Vacuum Society
• /
• v.20 no.6
• /
• pp.422-429
• /
• 2011

Dependence of radical and ion density on electron density and temperature is numerically investigated for $Cl_2$/Ar, $CF_4$, $CF_4/O_2$, $CF_4/H_2$, $C_2F_6$, $C_4F_8$ and $SF_6$ discharges which are widely used for etching process. We derived a governing equation set for radical and ion densities as functions of the electron density and temperature, which are easier to measure relatively, from continuity equations by assuming steady state condition. Used rate coefficients of reactions in numerical calculations are directly produced from collisional cross sections or collected from various papers. If the rate coefficients have different values for a same reaction, calculation results were compared with experimental results. Then, we selected rate coefficients which show better agreement with the experimental results.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.08a
• /
• pp.298-298
• /
• 2013

Finding renewable and clean energy resources is essential research to solve global warming and depletion of fossil fuels in modern society. Recently, complex harvesting of energy from multiple sources is available in our living environments using a single device has become highly desirable, representing a new trend in energy technologies. We report that when simultaneously driving the fusion and composite cells of two or more types, it is possible to make an affect the other cells to obtain a greater synergistic effect. To understand the coupling effect of photovoltaic and piezoelectric device, we fabricate the serially integrated hybrid cell (s-HC) based on organic solar cell (OSC) and piezoelectric nanogenerator (PNG). The size of increased voltage peaks when OSC and PNG are working on is larger than the case when only PNG is working. This voltage difference is the Voc change of OSC, not the voltage change of PNG and current density difference between these two cases is manifested more clearly. When the OSC and PNG are working in s-HC at the same time, piezoelectric potential (VPNG) is generated in ZnO and theoretical total voltage is sum of voltage of an OSC (VOSC) and VPNG. However, electrons from OSC are influenced by piezoelectric potential in ZnO and current loss of OSC in whole circuit decreases. As a result, VOSC increases temporarily. Current shows the similar behavior. PNG acts a resistance in the whole circuit and current loss occurs when the electrons from OSC pass through the PNG. But piezoelectric potential recover current loss and decrease the resistance of PNG. Our PNG can maintain piezoelectric potential when the strain is held owing to the LDH layer while general PNG cannot maintain piezoelectric potential. During the section that strain is held, voltage enhancement effect is maintained and same effect appeared even turn off the light. Actually at this time, electrons in ZnO nanosheets move to LDH and trapped by the positive charges in this layer. After this strain is held, piezoelectric potential of ZnO nanosheets is disappeared but potential difference which is developed by negative charge dominant LDH layer is remained. This potential acts similar role like piezoelectric potential in ZnO. Electrons from the OSC also are influenced by this potential and the more current flows.

• Journal of the Korean Vacuum Society
• /
• v.22 no.4
• /
• pp.181-187
• /
• 2013

$Dy^{3+}$-doped $BaMoO_4$ phosphor powders were synthesized by using the solid-state reaction method and their crystalline structure, morphology and size of particles, excitation and emission properties were investigated. The structure of all the phosphor powders, irrespective of the mol ratio of $Dy^{3+}$ ions, was found to be the tetragonal system with the main diffraction peak at (112) plane. The grain particles agglomerate together to form larger clusters with increasing the mol ratio of $Dy^{3+}$ ions. The excitation spectra were composed of a broad band centered at 293 nm and weak multiline peaked in the range of 230~320 nm, which were due to the transitions of $Dy^{3+}$ ions. The emission of the phosphors peaking at 666 and 754 nm, originating from the transitions of $^4F_{9/2}{\rightarrow}^6H_{11/2}$ and $^4F_{9/2}{\rightarrow}^6H_{9/2}$ of $Dy^{3+}$ ions, was rather weak, while the intensity of blue and yellow emission peaking at 486 nm and 577 nm due to the transitions of $^4F_{9/2}{\rightarrow}^6H_{15/2}$ and $^4F_{9/2}{\rightarrow}^6H_{13/2}$ of $Dy^{3+}$ ions was significantly stronger. The experimental results suggest that the white-light emission can be realized by controlling the yellow-to-blue intensity ratio of $Dy^{3+}$ emission.

• Korean Journal of Microbiology
• /
• v.41 no.4
• /
• pp.300-305
• /
• 2005

A transcriptionally active fragment $(P_{19})$ isolated by utilizing the promoter-probe shuttle vector pSK1Cat was analyzed. By subcloning analysis, the 180 bp region $(P_{180})$ responsible for the activity was determined. Transcriptional fusion of the C. glutamicum metX gene to $P_{180}\;(P_{180}-metX)$ resulted in a 24-fold increase in MetX activity in a complex medium, while a 13-fold increase was observed with the $P_{tac}$ promoter. Additionally, the expression conferred by $P_{180}$ was not affected by methionine added to the growth medium, suggesting that the $P_{180}$ clone is useful for the deregulated expression of biosynthetic genes in C. glutamicum during amino acid fermentation. Introduction of $P_{180}-metX$ into a lysine-producing C. glutamicum resulted in the production of methionine to 0.8 g/l.