Mobile service oriented architectures for NN-queries

The ever-increasing number of mobile device users has also raised the users’ expectation of mobile services accordingly. This phenomenon has given pressures to the mobile service providers to improve their services in order to stay competitive in the market. The service oriented approach is seen to be a promising scheme for mobile services. This paper presents mobile service oriented architectures for Nearest-Neighbor (NN) queries that are classified into five categories, namely (i) intermittent query mobile services, (ii) continuous query mobile services, (iii) context-aware mobile services, (iv) continuous moving object query mobile services, and (v) data broadcast mobile services. These services incorporate query, location and context-aware services, ontological context model, and broadcast. The proposed architectures are concerned with mobile services for clients on the move requesting services based on their current location, which is arguably the most important feature in a wireless environment. Furthermore, we also discuss the Quality-of-Service (QoS) requirement for mobile services in which request latency time is one of the most important parameters to consider. Some analytical models for query latency measurement are presented and the results are compared with the simulation experiments.     

Peer-to-peer bichromatic reverse nearest neighbours in mobile ad-hoc networks

The increasing use of mobile communications has raised many issues of decision support and resource allocation. A crucial problem is how to solve queries of Reverse Nearest Neighbour (RNN). An RNN query returns all objects that consider the query object as their nearest neighbour. Existing methods mostly rely on a centralised base station. However, mobile P2P systems offer many benefits, including self-organisation, fault-tolerance and load-balancing. In this study, we propose and evaluate 3 distinct P2P algorithms focusing on bichromatic RNN queries, in which mobile query peers and static objects of interest are of two different categories, based on a time-out mechanism and a boundary polygon around the mobile query peers. The Brute-Force Search Algorithm provides a naive approach to exploit shared information among peers whereas two other Boundary Search Algorithms filter a number of peers involved in query processing. The algorithms are evaluated in the MiXiM simulation framework with both real and synthetic datasets. The results show the practical feasibility of the P2P approach for solving bichromatic RNN queries for mobile networks.     

A pure peer-to-peer approach for kNN query processing in mobile ad hoc networks

Together with advanced positioning and mobile technologies, P2P query processing has attracted a growing interest number of location-aware applications such as answering kNN queries in mobile ad hoc networks. It not only overcomes drawbacks of centralized systems, for example single point of failure and bottleneck issues, but more importantly harnesses power of peers’ collaboration. In this research, we propose a pure mobile P2P query processing scheme which primarily focuses on the search and validation algorithm for kNN queries. The proposed scheme is designed for pure mobile P2P environments with the absence of the base station support. Compared with centralized and hybrid systems, our system can reduce energy consumption more than six times by making use of data sharing from peers in a reasonable mean latency of processing time for networks with high density of moving objects as can be seen in the simulation results.     

The Role of Electron Localization in Covalency and Electrochemical Properties of Lithium-Ion Battery Cathode Materials

Following the fundamental research conducted by J. B. Goodenough, the important role of electron localization induced by elemental substitution is studied. The size and electron negativity of host and substituting ions are two important factors in tuning material properties such as local structure and transition metal (TM) oxygen covalency. However, another factor, electron localization, which is widely studied in catalyst research but largely overlooked for battery materials, deserves systematic studies. A combined investigation using synchrotronbased X-ray spectroscopy and theoretical calculations is carried out on the Li-Co-Mn-O model system in which the substituting cation Mn⁴⁺, with its 3d³ electronic structure, is used as a promoter for electron localization. Results indicate that electron localization greatly influences the Co O bond by making it less covalent, which increases the delithiation voltage. It is also found that during charge/discharge, electron localization tends to make TM K-edge X-ray absorption near edge spectroscopy (XANES) spectra show a more “rigid shift” behavior while electron delocalization makes the XANES exhibit a “shape change.” It clearly explains why the K-edge XANES data of some TM oxides show no “rigid shift” while the nominal valence states changed. This work highlights the importance of electron localization with guidance for XANES interpretation.     

Numerical study of 2024 T3 aluminum plates subjected to impact and perforation

The paper describes a work focused on the process of perforation of aluminum sheet. A numerical investigation has been carried out to analyze in details the perforation process subjected to normal impact by different nose shapes of projectiles. The perforation process has been simulated by the application of 3D analysis using IMPACT dynamic FE program suite. The comparison on failure modes depending on the projectile nose shape have been studied and evaluated. An appropriate constitutive relation was applied to describe the material behavior of the aluminum sheet. The study covered different failure modes including petalling, plug ejection and circumference necking of perforated aluminum sheet according to different level of impact velocity ranging from 100 m/s to 600 m/s. In this investigation, a special attention will be given on the deformation and failure.     

Identification of 3,4-Dihydro-2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine Derivatives as Novel Selective Inhibitors of Plasmodium falciparum Dihydroorotate Dehydrogenase

Plasmodium falciparum’s resistance to available antimalarial drugs highlights the need for the development of novel drugs. Pyrimidine de novo biosynthesis is a validated drug target for the prevention and treatment of malaria infection. P. falciparum dihydroorotate dehydrogenase (PfDHODH) catalyzes the oxidation of dihydroorotate to orotate and utilize ubiquinone as an electron acceptor in the fourth step of pyrimidine de novo biosynthesis. PfDHODH is targeted by the inhibitor DSM265, which binds to a hydrophobic pocket located at the N-terminus where ubiquinone binds, which is known to be structurally divergent from the mammalian orthologue. In this study, we screened 40,400 compounds from the Kyoto University chemical library against recombinant PfDHODH. These studies led to the identification of 3,4-dihydro-2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine and its derivatives as a new class of PfDHODH inhibitor. Moreover, the hit compounds identified in this study are selective for PfDHODH without inhibition of the human enzymes. Finally, this new scaffold of PfDHODH inhibitors showed growth inhibition activity against P. falciparum 3D7 with low toxicity to three human cell lines, providing a new starting point for antimalarial drug development.     

Effects of amino acid substitution on the physicochemical properties of artificial proteins with random sequences

Physicochemical properties of four random proteins, each consisting of about 150 amino acid residues with different sequence identity, were compared to know the correlation between the physicochemical properties and its sequence. The results showed that the extent of the sequence alterations correlated well with the extent of differences in CD spectra, roughly with those in pH-solubility profiles and sedimentation velocity, and not with that in the binding of a hydrophobic fluorescent dye (ANS). Therefore, proteins with similar sequences can have different physicochemical properties, indicating that the extent of mutational effects varies in response to the sequence being altered. This warrants the evolution of a protein in a sequence-specific manner.     

Enzymatic Saccharification of Soda Pulp from Sago Starch Waste Using Sago Lignin-Based Amphipathic Derivatives

The aim of this research is to develop an enzymatic saccharification process of sago starch waste, with a small charge of cellulase. The waste contained a significant amount of residual starch, which was recovered as glucose by mild acid hydrolysis. The starch-free residue was subjected to soda-anthraquinone pulping to yield soda pulp and soda lignin. The lignin was converted to amphipathic lignin derivatives by the reaction with epoxylated polyethylene glycol analogues. The pulp was hydrolyzed with cellulase (Genencor GC220), with the amphipathic derivatives, to yield glucose. The lignin derivative-assisted, enzymatic saccharification was repeatedly conducted by reusing cellulase recovered by ultrafiltration from saccharification media. Saccharification efficiency with the derivatives was maintained at a high level even after the fourth run of saccharification, while the efficiency was remarkably decreased by repeated use of cellulase without additive. Thus, the amphipathic sago lignin derivatives enabled repeated use of cellulase for saccharification of sago starch waste.     

A path following control of an unmanned autonomous forklift

In this paper, the development of an unmanned autonomous forklift is discussed. A system configuration using vision, laser ranger finder, sonar, etc. for autonomous navigation is presented. The kinematics of a spin-turn mechanism is analyzed first, and then the obtained kinematics equations are transformed to the equations represented by path variables. These equations are nonlinear state equations to be used for control purposes. A time varying feedback control law via the chained form of Murray and Sastry [12] is derived. The effectiveness of the proposed control law is examined through simulations and experiments. Recommended by Editorial Board member Sooyong Lee under the direction of Editor Jae-Bok Song. This work was supported by the Korea Research Foundation Grant funded by the Korean Government (MOEHRD) (The Regional Research Universities Program/Institute of Logistics Information Technology). Tua Agustinus Tamba received the B.S. degree in Engineering Physics from Institute of Technology Bandung, Indonesia, in 2006. He is currently a graduate student at the School of Mechanical Engineering, Pusan National University, Busan, Korea. His research interests include control of unmanned vehicles and path planning technologies for autonomous robots. Bonghee Hong received the B.S., M.S., and Ph.D. degrees in Computer Science and Engineering from Seoul National University in 1982, 1984, and 1988, respectively. Dr. Hong joined the Department of Computer Science and Engineering at Pusan National University (PNU) in 1989 and now he is a Professor. Dr. Hong is the Director of the Research Institute of Logistics Information Technology (LIT) at PNU. Dr. Hong received the Korean Minister Award in 2006 and the University Excellence Innovation Award in 2007. His current research interests include theory of database systems, RTLS systems, RFID middleware, RFID database, and stream data processing. Keum-Shik Hong received the B.S. degree in Mechanical Design and Production Engineering from Seoul National University in 1979, the M.S. degree in Mechanical Engineering from Columbia University, New York, in 1987, and both the M.S. degree in Applied Mathematics and the Ph.D. degree in Mechanical Engineering from the University of Illinois at Urbana-Champaign (UIUC) in 1991. From 1991 to 1992, he was a Postdoctoral Fellow at UIUC. Since Dr. Hong joined the School of Mechanical Engineering at Pusan National University, Korea, in 1993, he is now a Professor. During 1982–85, he was with Daewoo Heavy Industries, Incheon, Korea, where he worked on vibration, noise, and emission problems of vehicles and engines. Dr. Hong serves as Editor-in-Chief of the Journal of Mechanical Science and Technology and serves as an Associate Editor in various IEEE and IFAC conferences editorial boards. He also served as an Associate Editor for the Journal of Control, Automation, and Systems Engineering and has been serving as an Associate Editor for Automatica (2000–2006) and as an Editor for the International Journal of Control, Automation, and Systems (2003–2005). His laboratory, Integrated Dynamics and Control Engineering Laboratory, was designated as a National Research Laboratory by the Ministry of Science and Technology of Korea in 2003. Dr. Hong received Fumio Harashima Mechatronics Award in 2003 and the Korean Government Presidential Award in 2007. He is a Member of ASME, IEEE, ICROS, KSME, KSPE, KIEE, and KINPR. Dr. Hong’s current research interests include nonlinear systems theory, adaptive control, distributed parameter system control, robotics, vehicle control, and innovative control applications to engineering problems.     

Protective coating based on manganese–copper oxide for solid oxide fuel cell interconnects: Plasma spray coating and performance evaluation

A solid oxide fuel cell (SOFC) stack requires metallic interconnects to electrically connect unit cells, while preventing fuel from mixing with oxidant. During SOFC operations, chromia scales continue to grow on the interconnect surfaces, resulting in a considerable increase of interfacial resistance, and at the same time, gaseous Cr species released from the chromia scales degrades the cathode performance. To address these problems, in this study, protective Mn₂CuO₄ coatings are fabricated on metallic interconnects (Crofer 22 APU) via a plasma spray (PS) process. The PS technique involves direct spray deposition of molten Mn₂CuO₄ onto the interconnect substrate and leads to the formation of high-density Mn₂CuO₄ coatings without the need for post-heat-treatment. The thickness, morphology, and porosity of the PS-Mn₂CuO₄ coating are found to depend on the processing parameters, including plasma arc power, gas flow rate, and substrate temperature. The PS-Mn₂CuO₄ coating fabricated with optimized parameters is completely impermeable to gases and has high adhesion strength on the interconnect substrate. Furthermore, no resistive chromia scales are formed at the coating/substrate interface during the PS process. As a result, the PS-Mn₂CuO₄-coated interconnects show a very low area-specific resistance below 10?mΩ?cm² at 800?°C in air and excellent stability during both continuous operation and repeated thermal cycling. This work suggests that an appropriate combination of the material and coating process provides a highly effective protective layer for SOFC interconnects.