Embedding of Virtual Network Requests over Static Wireless Multihop Networks

Network virtualization is a technology of running multiple heterogeneous network architecture on a shared substrate network. One of the crucial components in network virtualization is virtual network embedding, which provides a way to allocate physical network resources (CPU and link bandwidth) to virtual network requests. Despite significant research efforts on virtual network embedding in wired and cellular networks, little attention has been paid to that in wireless multi-hop networks, which is becoming more important due to its rapid growth and the need to share these networks among different business sectors and users. In this paper, we first study the root causes of new challenges of virtual network embedding in wireless multi-hop networks, and propose a new embedding algorithm that efficiently uses the resources of the physical substrate network. We examine our algorithm's performance through extensive simulations under various scenarios. Due to lack of competitive algorithms, we compare the proposed algorithm to five other algorithms, mainly borrowed from wired embedding or artificially made by us, partially with or without the key algorithmic ideas to assess their impacts.Comment: 22 page

Nutritional, Bone, and Physical Fitness States of Jockeys in Chronic Repetition of Short-Term Weight Loss

Professional jockeys are required to fit their weight, mainly weight loss, for two game days every weekend during racing season which usually lasts 10 months a year in Korea. The repetitive routine weight loss protocol is performed for 4 to 5 days a week include two game days. This situation would have brought some negative effects on the professional jockeys\u27 overall health and physical condition with the relation of their performance. The purpose of the present study was: 1) to examine the weight loss habits of pro-jockeys, and 2) effects of chronic short-term weight loss on nutritional status, bone health, and physical fitness of them. Pro jockeys (n=43) completed a questionnaire for the assessment of weight loss habits. Pro jockeys (n=10, around 12 years of career) were compared with trainee jockeys (n=10, less than 1 years of career) for their nutritional status, bone health, and physical fitness. The nutritional status was measured by a computerized program (CAN Pro 2.0). Bone mineral density was measured by DEXA (Hologic, QDR-4500W, USA). All participants performed grip strength test, standing on one leg with eyes closed test, and side step test for the assessment of physical fitness. According to the result, more than 80% of pro jockeys underwent a routine weight loss process every week, for around 1 kg, within 2 to 3 days prior to the game days by diet mainly and/or exercise/sauna. Around 70% of them reported severe fatigue during the weight loss period. There were no significant differences in nutritional status between two groups. However, they consume average of 1,100 Kcal a day reflecting 21 to 80% of recommended daily consumption during weight loss periods. In bone health, six trainee jockeys and two pro jockeys were diagnosed as osteopenia. One pro jockey was diagnosed as osteoporosis. No significant difference was found in fitness factors between two groups. In conclusion, chronic exposure to short-term weight loss may result in serious health problems especially on bone health. For the jockeys in Korea, balanced diet program and the related education on weight management are strongly required.

Successive spin-flop transitions of a Neel-type antiferromagnet Li2MnO3 single crystal with a honeycomb lattice

We have carried out high magnetic field studies of single-crystalline Li2MnO3, a honeycomb lattice antiferromagnet. Its magnetic phase diagram was mapped out using magnetization measurements at applied fields up to 35 T. Our results show that it undergoes two successive meta-magnetic transitions around 9 T fields applied perpendicular to the ab plane (along the c* axis). These phase transitions are completely absent in the magnetization measured with the field applied along the ab plane. In order to understand this magnetic phase diagram, we developed a mean-field model starting from the correct Neel-type magnetic structure, consistent with our single crystal neutron diffraction data at zero field. Our model calculations succeeded in explaining the two meta-magnetic transitions that arise when Li2MnO3 enters two different spin-flop phases from the zero field Neel phase.open1187Nsciescopu

Controlling the Electrical Properties of Undoped and Ta-doped TiO2 Polycrystalline Films via Ultra-Fast Annealing Treatments

We present a study on the crystallization process of undoped and Ta doped TiO2 amorphous thin films. In particular, the effect of ultra-fast annealing treatments in environments characterized by different oxygen concentrations is investigated via in-situ resistance measurements. The accurate examination of the key parameters involved in this process allows us to reduce the time needed to obtain highly conducting and transparent polycrystalline thin films (resistivity about $6 \times 10^{-4}$ {\Omega}cm, mean transmittance in the visible range about $81\%$) to just 5 minutes (with respect to the 180 minutes required for a standard vacuum annealing treatment) in nitrogen atmosphere (20 ppm oxygen concentration) at ambient pressure. Experimental evidence of superficial oxygen incorporation in the thin films and its detrimental role for the conductivity are obtained by employing different concentrations of traceable 18O isotopes during ultra-fast annealing treatments. The results are discussed in view of the possible implementation of the ultra-fast annealing process for TiO2-based transparent conducting oxides as well as electron selective layers in solar cell devices; taking advantage of the high control of the ultra-fast crystallization processes which has been achieved, these two functional layers are shown to be obtainable from the crystallization of a single homogeneous thin film.Comment: 30 pages (including Supporting Information and graphical TOC), 4 figure

Synergistic multi-doping effects on the Li7La3Zr2O12 solid electrolyte for fast lithium ion conduction.

Here, we investigate the doping effects on the lithium ion transport behavior in garnet Li7La3Zr2O12 (LLZO) from the combined experimental and theoretical approach. The concentration of Li ion vacancy generated by the inclusion of aliovalent dopants such as Al(3+) plays a key role in stabilizing the cubic LLZO. However, it is found that the site preference of Al in 24d position hinders the three dimensionally connected Li ion movement when heavily doped according to the structural refinement and the DFT calculations. In this report, we demonstrate that the multi-doping using additional Ta dopants into the Al-doped LLZO shifts the most energetically favorable sites of Al in the crystal structure from 24d to 96 h Li site, thereby providing more open space for Li ion transport. As a result of these synergistic effects, the multi-doped LLZO shows about three times higher ionic conductivity of 6.14 × 10(-4) S cm(-1) than that of the singly-doped LLZO with a much less efforts in stabilizing cubic phases in the synthetic condition

Flexible ultraviolet and ambient light sensor based on nanomaterial network fabricated by using selective and localized wet-chemical reactions

We report ZnO nanowire- and TiO_2 nanotube-based light sensors on flexible polymer substrates fabricated by localized hydrothermal synthesis and liquid phase deposition (LPD). This method realized simple and cost-effective in situ synthesis and integration of one-dimensional ZnO and TiO_2 nanomaterials. The fabricated sensor devices with ZnO nanowires and TiO_2 nanotubes show very high sensitivity and quick response to the ultraviolet (UV) and ambient light, respectively. In addition, our direct synthesis and integration method result in mechanical robustness under external loading such as static and cyclic bending because of the strong bonding between the nanomaterial and the electrode. By controlling the reaction time of the LPD process, the Ti/Zn ratio could be simply modulated and the spectral sensitivity to the light in the UV to visible range could be controlled