This paper proposes a three-dimensional uniform ultra-high frequency (UHF) near-field radio frequency identification (RFID) reader antenna. The antenna achieves a uniform electric field in the x and y directions by placing a single branch microstrip line along the x-axis and y-axis directions, respectively. It reaches a uniform electric field in the z-direction by a centrosymmetric four-branch microstrip line. The proposed antenna achieves three-dimensional direction uniformity through a reconfigurable method. The impedance matching bandwidth range of S11 <−10 dB for simulation and measurement includes 0.66 to 0.98 GHz, which can meet the near-field RFID operation frequency band demand. The isolation degrees between ports are less than −24.6 dB within the UHF RFID frequency band (0.86 to 0.96 GHz). In addition, the antenna also has the characteristic of low gain in the far field, and the maximum gain in the far field is less than −27 dBi when operating at different ports. The test results show that the proposed antenna three-dimensional uniform volume of dipole tags above the antenna is 99 mm × 99 mm × 20 mm, and the reading volume of the near-field tags is 40 mm × 40 mm × 5 mm. When the tags are placed on a book, there will be a slight variation in the reading range of the tags.

This paper presents two novel UHF RFID near-field reader antennas with uniform vertical electric field distribution. The two antennas have the following common characteristics. First, the radiating parts of the two antennas are simulated and fabricated by the microstrip lines and work using the leakage wave principle of microstrip lines. Second, the end of microstrip lines match the load to form a traveling wave mode of operation, so the two antennas have broadband characteristics. Third, both antennas are fed in a coaxial manner at the center of the antenna. The simulation and measurement results can show that the proposed three-branch antenna and four-branch antenna achieve good impedance matching in the range of 883–960 MHz and 870–960 MHz, respectively, and achieve uniform distribution of the vertical electric field component in a certain area. The reading areas of the three-branch antenna and the four-branch antenna are 70 mm × 70 mm × 90 mm and 100 mm × 100 mm × 120 mm (length × width × height), respectively. Due to the introduction of the ground plate, the antenna gain is low, which meets the design requirements of near-field antennas.

A novel multi-polarized UHF RFID reader antenna for near-field applications is presented. Based on capacitive coupling and standing-wave structure, the antenna is designed and fabricated by microstrip lines. By designing the number of units that consists of an antenna, the interrogated area can be adjusted flexibly and easily. In the interrogated area, the antenna can generate uniform and multi-polarization electric field distributions to detect arbitrarily oriented linearly polarized tags in the horizontal plane. The measured results show that the antenna achieves impedance matching from 893 to 935 MHz.

This paper presents a multipolarized reader antenna with periodic units based on electric field coupling for near-field applications of ultra-high frequency (UHF) radio frequency identification (RFID). The antenna units are composed of two branches that are mirror-symmetric with respect to the x-axis and produce +/- 45 degrees linear polarization. A 90 degrees phase difference is produced between the upper and lower branches by introducing a phase shifter into the upper branch, so that the near-field electric fields excited in the horizontal plane exhibit a quasi-circular polarization distribution. The proposed design is validated by simulations and experiments using prototype 4-unit and 6-unit antennas. The proposed antennas can generate strong and uniform electric fields and provide reading volumes of 400 mm x 320 mm x 300 mm and 560 mm x 320 mm x 300 mm for the 4-unit and 6-unit antennas, respectively, regardless of the orientation of the tags in the horizontal plane. In addition, the far-field gain is low with a maximum of -6 dBi, thus the misreading of tags outside the reading region is avoided. The proposed antenna achieves impedance matching over the Chinese UHF RFID band (920-925 MHz) and therefore meets the application requirements of near-field RFID reader antennas.

To explore the relationship between yin-deficiency constitution (YDC) and biochemical indexes by way of observing the endocrinal and immune functions in subjects with YDC.

The synthesis of 3 beta-hydroxy-24-norchol-5-en-23-oic acid, an anti-inflammatory marine natural product, was achieved from commercial available 16-dehydropregnenolone acetate in six steps with a 28.2% overall yield. The key step was palladium catalyzed allylation.

The synthesis of (20S)-20-hydroxycholestane-3,16-dione, a marine natural product against four tumor cell lines (ED50=1 μg/mL), was achieved from 16-dehydropregnenolone acetate in seven steps with a 13.1% overall yield. The key step was a substrate controlled asymmetric heteroatom conjugated addition.

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The first synthesis of beta-(pregna-5,20-diene-3 beta-yl)-D-xylopyranoside was achieved from 16-dehydropregnenolon-3 beta-yl acetate in six steps with a 15.0% overall yield. The key steps were selective reduction of alpha,beta-unsaturated ketone, Shapiro reaction and Koenig-Knorr reactions.

The asymmetric synthesis of (+)-(11R,12S)-mefloquine hydrochloride, an antimalarial drug, was accomplished from commercially available 2-trifluoromethylaniline, ethyl 4,4,4-trifluoroacetoacetate and cyclopentanone in 7 steps with a 14% overall yield. The key steps were proline-catalyzed asymmetric direct aldol reaction and Beckmann rearrangement. The absolute configuration was assigned by a Mosher's method.

This paper presents an efficient content search system, which is applied to iShare, a distributed peer-to-peer(P2P) Internet-sharing system. iShare facilitates the sharing of diverse resources located in different administrative domains over the Internet. For efficient resource management, iShare organizes resources into a hierarchical name space, which is distributed over the underlying structured P2P network. However, iShare's search capability has a fundamental limit inherited from the underlying structured P2P system's search capability. Most existing structured P2P systems do not support content searches. There exists some research that provides content search functionality, but the approaches do not scale well and incur substantial overheads on data updates. To address these issues, we propose an efficient hierarchical-summary system, which enables an efficient content search and semantic ranking capability over traditional structured P2P systems. Our system uses a hierarchical name space to implement a summary hierarchy on top of existing structured P2P overlay networks, and uses a Bloom Filter as a summary structure to reduce space and maintenance overhead. We implemented the proposed system in iShare, and the results show that our search system finds all relevant results regardless of summary scale and the search latency increases very slowly as the network grows.

This paper presents iShare, a distributed peer-to-peer Internet-sharing system, that facilitates the sharing of diverse resources located in different administrative domains over the Internet. iShare addresses the challenges of resource management in desktop grids, and integrates these resources with production grids. In this paper, we present a brief overview of the iShare system and describe how iShare leverages existing standards to provide novel solutions to the problems of resource dissemination, resource allocation and trust in desktop grids. We also discuss how iShare integrates production grid systems, such as the Teragrid, with desktop resources and compare the iShare approach with Web-based user portals for production grids. To quantitatively evaluate our techniques, we measured the efficiency of resource allocation in iShare and the overheads associated with establishing trust and providing the iShare user interface for production grids. The evaluation results demonstrate that iShare enables open Internet sharing with efficiency, reliability, and security.

Fine-Grained Cycle Sharing (FGCS) systems aim at utilizing the large amountof idle computational resources available on the Internet. Such systems allow guest jobs to run on a host if they do not significantly impact the local users of the host. Since the hosts are typically provided voluntarily, their availability fluctuates greatly. To provide fault tolerance to guest jobs without adding significant computational overhead, we propose failure-aware checkpointing techniques that apply the knowledge of resource availability to select checkpoint repositories and to determine checkpoint intervals. We present the schemes of selecting reliable and efficient repositories from the non-dedicated hosts that contribute their disk storage. These schemes are formulated as 0/1 programming problems to optimize the network overhead of transferring checkpoints and the work lost due to unavailability of a storage host when needed to recover a guest job. We determine the checkpoint interval by comparing the cost of checkpointing immediately and the cost of delaying that to a later time, which is a function of the resource availability. We evaluate these techniques on an FGCS system called iShare, using trace-based simulation. The results show that they achieve better application performance than the prevalent methods which use checkpointing with a fixed periodicity on dedicated checkpoint servers.

Fine-grained cycle sharing (FGCS) systems aim at utilizing the large amount of computational resources available on the Internet. In FGCS, host computers allow guest jobs to utilize the CPU cycles if the jobs do not significantly impact local host users. Such resources are generally provided voluntarily and their availability fluctuates highly. Guest jobs may fail unexpectedly, as resource becomes unavailable. We present empirical studies on the detection and predictability of resource availability in FGCS systems. A multi-state availability model is derived from a study of resource behavior. The model combines generic hardware-software failures with domain-specific resource behavior in FGCS. To understand the predictability, we traced resource availability in a production FGCS system for three months. We found that the daily patterns of resource availability are comparable to those in recent history. This observation suggests the feasibility of predicting future resource availability, which can be applied for proactive management of guest jobs

Internet sharing systems aim at federating and utilizing distributed computing resources across the Internet. This paper presents a user-level virtual machine (VM) approach to MPI program execution in an Internet sharing framework. In this approach, the resource consumer has its own operating system running on top of and isolated from, the operating system of the resource provider. We propose an efficient socket virtualization technique to optimize VM network performance. Socket virtualization achieves the same network bandwidth as the physical network. In our LAN environment, it reduces the latency overhead from 112% (using existing TUN/TAP technique) to 35.6%. Performance results on MPI benchmarks show that our virtualization technique incurs small overhead compared with the physical host platform, while gaining in return a higher degree of guest isolation and customization. We also describe the key mechanisms that allow the employment of VMs in an existing Internet sharing system

Fine-grained cycle sharing (FGCS) systems aim at utilizing the large amount of computational resources available on the Internet. In FGCS, host computers allow guest jobs to utilize the CPU cycles if the jobs do not significantly impact the local users of a host. A characteristic of such resources is that they are generally provided voluntarily and their availability fluctuates highly. Guest jobs may fail because of unexpected resource unavailability. To provide fault tolerance to guest jobs without adding significant computational overhead, it requires to predict future resource availability. This paper presents a method for resource availability prediction in FGCS systems. It applies a semi-Markov Process and is based on a novel resource availability model, combining generic hardware-software failures with domain-specific resource behavior in FGCS. We describe the prediction framework and its implementation in a production FGCS system named iShare. Through the experiments on an iShare testbed, we demonstrate that the prediction achieves accuracy above 86% on average and outperforms linear time series models, while the computational cost is negligible. Our experimental results also show that the prediction is robust in the presence of irregular resource unavailability