Several flash file systems have been developed based on the physical characteristics of NAND flash memory. However, previous flash file systems have performance overhead and scalability problems ...caused by metadata management in NAND flash memory. In this paper, we present a flash file system called PFFS2. PFFS2 stores all metadata into virtual metadata storage, which employs Phase-change RAM (PRAM). PRAM is a next-generation nonvolatile memory and will be good for dealing with word-level read/write of small-size data. Based on the virtual metadata storage, PFFS2 can manage metadata in a virtually fixed location and through byte-level in-place updates. Therefore, the performance of PFFS2 is 38 percent better than YAFFS2 for small file read/write while matching YAFFS2 performance for large file. Virtual metadata storage is particularly effective in decreasing the burden of computational and I/O overhead of garbage collection. In addition, PFFS2 maintains a 0.18 second mounting time and 284 KB memory usage in spite of increases in NAND flash memory size. We also propose a wear-leveling solution for PRAM in virtual metadata storage and greatly reduce the total write count of NAND flash memory. In addition, the life span of PFFS2 is longer than other flash file systems.
Closed-form expressions of radiated emissions from power distribution networks (PDNs) in packages are derived based on the equivalent lumped-circuit model. The expressions are validated with results ...from full-wave numerical computations and far-field measurements. The effects of the small planar PDN structures on radiated emissions are quantitatively investigated based on the sensitivity analysis. Using the closed-form expressions, a systematic procedure for developing quantified PDN design guidelines to suppress the radiated emissions is formulated, which is then demonstrated with a test prototype PDN. The method allows the electromagnetic compatibility aware PDN design in the initial design stage.
Statistical link analysis methods were previously developed for effective computation of bit error rate due to intersymbol interference (ISI). In addition to ISI, supply voltage fluctuations at ...output drivers can cause jitter and amplitude uncertainty in I/O links. In this paper, the enhanced statistical link analysis method considering both ISI and supply voltage fluctuations is clearly reformulated and experimentally validated step by step by various measurements. A silicon integrated circuit (IC) is designed, fabricated, and assembled on a manufactured printed circuit board (PCB). The supply voltage fluctuations on the IC with regard to the receiver reference voltage are extracted from measurements at the IC and PCB. Also, the impulse response of the total output channel is extracted from the measurements of the driver and channel characteristics. The statistical eye diagrams of the channel output including both ISI effects and the supply voltage fluctuations are then calculated and validated by comparison with the direct eye measurements.
Numerous scaling limitations of NAND flash memory have arisen due to the intrinsic nature of the operational principle of NAND flash memory and those limitations eventually lead to a paradigm shift ...in the NAND flash technology from the planar cell to the vertical NAND cell. In this paper, the limitations of scaling which induce the evolution of the NAND cell as well as the current trends of NAND technology are reviewed.
Endurance degradation model applicable to the broad node range of floating-gate NAND flash memory is proposed for the first time. The model is based on generation of the trapped charge, which follows ...nonuniform spatial distribution of the erase tunneling current. A special Topology Computer-Aided Design (TCAD) simulation technique to simulate program/erase cycling is described in detail. Simulation parameters, determining change of midgap voltage (vertical centroid position and maximum value of the trapped charge) are extracted from the reference device with known endurance curve, and these are applied to the target cell. The endurance characteristics predicted by the model are verified to reproduce measured endurance curves for design rules of 27, 42, and 90 nm. Several factors affect midgap voltage change-area occupied by trapped charge; vertical position of charge centroid; separation of trapped charge distribution and tunnel current. A 3-D TCAD simulation allows accurate consideration of the given factors, resulting in good match between measured and simulated endurance curves.
The step response of a single ended output driver with silicon interposer channel is derived including the parasitics of ESD protection circuits. The probability density functions of the output ...voltage due to supply voltage fluctuations are also analytically calculated. With changing the frequency of supply voltage fluctuations, the effect of ESD parasitics on the output jitter is calculated and compared.
Antibody Engineering for the Development of Therapeutic Antibodies Kim, S.J. (Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea); Park, Y.W. (Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea); Hong, H.J. (Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea), E-mail: hjhong@kribb.re.kr
Molecules and cells,
08/2005, Letnik:
20, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Therapeutic antibodies represent one of the fastest growing areas of the pharmaceutical industry. There are currently 19 monoclonal antibodies in the market that have been approved by the FDA and ...over 150 in clinical developments. Driven by innovation and technological developments, therapeutic antibodies are the second largest biopharmaceutical product category after vaccines. Antibodies have been engineered by a variety of methods to suit a particular therapeutic use. This review describes the structural and functional characteristics of antibody and the antibody engineering for the generation and optimization of therapeutic antibodies.
Background: Cataracts are the leading cause of impaired vision or blindness in dogs. There are many antioxidants that can prevent cataract progression, but whether they are clinically effective in ...dogs has not been established. Objectives: To analyze the delaying or preventing effect of oral antioxidants on canine senile cataracts through retrospective analysis. Methods: Medical records of dogs from January 1, 2015 to July 10, 2020 were reviewed. Dogs that were 8 yr of age or older with senile cataracts were included in this study. The dogs were divided into two treatment groups (dogs administered with Ocu-GLO supplement and dogs administered with Meni-One Eye R/C supplement) and a control group (dogs that were not administered any supplement). Dogs with incipient and immature cataracts were included in this study. Altogether, 112 dogs (156 eyes) with incipient cataracts and 60 dogs (77 eyes) with immature cataracts were included. The period of time that cataracts progressed from incipient to immature, and from immature to mature was recorded for each dog. Results: There was no significant delaying effect on the progression of incipient cataracts. However, both Ocu-GLO (hazard ratio = 0.265, p = 0.026) and Meni-One (hazard ratio = 0.246, p = 0.005) significantly delayed the progression of immature cataracts compared to the control group. Conclusions: Although there was no significant delaying effect of oral antioxidants on incipient cataract progression, antioxidants could be used to delay the progression of senile immature cataract.
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