Long-term Information Preservation and Access

An unprecedented amount of information encompassing almost every facet of human activities across the world is generated daily in the form of zeros and ones, and that is often the only form in which such information is recorded. A good fraction of this information needs to be preserved for periods of time ranging from a few years to centuries. Consequently, the problem of preserving digital information over a long-term has attracted the attention of many organizations, including libraries, government agencies, scientific communities, and individual researchers. In this dissertation, we address three issues that are critical to ensure long-term information preservation and access. The first concerns the core requirement of how to guarantee the integrity of preserved contents. Digital information is in general very fragile because of the many ways errors can be introduced, such as errors introduced because of hardware and media degradation, hardware and software malfunction, operational errors, security breaches, and malicious alterations. To address this problem, we develop a new approach based on efficient and rigorous cryptographic techniques, which will guarantee the integrity of preserved contents with extremely high probability even in the presence of malicious attacks. Our prototype implementation of this approach has been deployed and actively used in the past years in several organizations, including the San Diego Super Computer Center, the Chronopolis Consortium, North Carolina State University, and more recently the Government Printing Office. Second, we consider another crucial component in any preservation system - searching and locating information. The ever-growing size of a long-term archive and the temporality of each preserved item introduce a new set of challenges to providing a fast retrieval of content based on a temporal query. The widely-used cataloguing scheme has serious scalability problems. The standard full-text search approach has serious limitations since it does not deal appropriately with the temporal dimension, and, in particular, is incapable of performing relevancy scoring according to the temporal context. To address these problems, we introduce two types of indexing schemes - a location indexing scheme, and a full-text search indexing scheme. Our location indexing scheme provides optimal operations for inserting and locating a specific version of a preserved item given an item ID and a time point, and our full-text search indexing scheme efficiently handles the scalability problem, supporting relevancy scoring within the temporal context at the same time. Finally, we address the problem of organizing inter-related data, so that future accesses and data exploration can be quickly performed. We, in particular, consider web contents, where we combine a link-analysis scheme with a graph partitioning scheme to put together more closely related contents in the same standard web archive container. We conduct experiments that simulate random browsing of preserved contents, and show that our data organization scheme greatly minimizes the number of containers needed to be accessed for a random browsing session. Our schemes have been tested against real-world data of significant scale, and validated through extensive empirical evaluations

Fabrication and Evaluation of Mechanical Properties of CF/GNP Composites

AbstractCNT/CFRP (Carbon Nanotube/ Carbon Fiber Reinforced Plastic) composites and GNP/CFRP (Graphene Nano platelet/ Carbon Fiber Reinforced Plastic) have several excellent mechanical properties including, high strength, young's modulus, thermal conductivity, corrosion resistance, electronic shielding and so on. In this study, CNT/CFRP composites were manufactured by varying the CNT weight ratio as 2wt% and 3wt%, While GNP/CFRP composites were manufactured by varying the GNP weight ratio as 0.5wt% and 1wt%. The composites ware manufactured by mechanical method (3-roll-mill). Tensile, impact and wear tests were performed according to ASTM standards D638, D256 and D3181 respectively. It was observed that, increasing the CNT weight ratio improves the mechanical properties, e.g., tensile strength, impact and wear resistance

Subpleural Pulmonary Hyalinizing Granuloma Presenting as a Solitary Pulmonary Nodule

AbstractWe introduce a case of pulmonary hyalinizing granuloma presented as a solitary pulmonary nodule located subpleurally. The patient was a 57-year-old man who had abnormal chest roentgenograms showing a solitary pulmonary nodule in the right lower lung field. The nodule was resected for definitive diagnosis and histopathologically proved to be pulmonary hyalinizing granuloma. In previously reported cases, most patients had ill-defined margins and usually bilateral, multiple lesions radiographically. In our case, the subpleural location is an uncommon location of this rare entity

Expression of Osteocalcin and Transglutaminase and Labelling of Bromodeoxyuridine during Fracture Healing in the Rat Tibia

The expression of osteocalcin and transglutaminase C(TGase C) during fracture healing was inwstigated with immunohistochemical studies. A transverse osteotomy was made at the proximal tibia in Sprague-Dawley male rats and immobilized with a small external skeletal fixator. The animals lU!l'e sacrificed serially I, 3, 5, 7, 14, 42 days respectively after fracture. Longitudinal sections of the healing bone were stained with pohclonal antibody against osteocalcin and TGase C, and monoclonal antibody against bromodeoxyuridine. During the intramembranous bone formation at the periosteum around the fracture site, osteocalcin was strongly expressed in the proliferating osteoprogenitor cells from the 1st day of fracture, and then, in osteoblasts, osteoid matrix and osteocytes. The expression of TGase C was weakly positive in both osteoprogenitor cells and osteoblasts. Ai the site of endochondral bone formation, which was first reoealed 5 days after fracture, cell proliferation occurred at the periphery of cartilaginous callus where the number of cells stained with BrdU was highest During the maturation of callus, those cells uere entrapped in the chondroid matrix and became larger and larger. Osteocalcin was demonstrated in the cytoplasm of chondrocytes, while chondroid matrix was negatiwly stained. TGase C was found in the cytoplasm of more centrally located and matured chondrocytes as compared with osteocalcin. Osteoid matrix was stained with osteocalcin but not with TGase C. These finding may suggest that osteocalcin participates in the early phase of endochondral bone formation, while TGase C participates in the late phase, suggesting the role of TGase C in matrix stabilization. But the reason for the difference in the expression of TGase C between the endochondral bone formation and intramembranous bone formation should be further inwstigated. Healing of IAA2Il immobilized fracture in this study was predominantly induced by intramembranous ossification rather than endochondral ossification. Periosteal osteoprogenitor cells appeared to initiate and to lead bone formation after osteotomy. These findings indicate that preservation of the periosteum is essential to achieve successful fracture healing

Angle-tolerant linear variable color filter based on a tapered etalon

We propose and fabricate a linear variable color filter (LVCF) that possesses an enhanced angular tolerance in conjunction with a wide linear filtering range (LFR) by taking advantage of an Ag-TiO2-Ag configuration. The TiO2 cavity is tapered in thickness along the device so that the resonance wavelength can be continuously tuned according to the position. In addition, the metal-dielectric-metal structure is overlaid with a pre-designed graded anti-reflection coating in SiO2 to complete the etalon, thereby maximizing the transmission efficiency across the entire device. The tapered dielectric layers in the proposed filter were fabricated via glancing angle deposition without the help of any mask or moving parts. The center wavelength was scanned from 410 nm to 566 nm, resulting in an LFR of 156 nm, and the overall spectra exhibited an approximate peak transmission of 40% and spectral bandwidth of 68 nm. The angular tolerance was as large as 45°, incurring a fractional wavelength shift below 4.2%. The resonance wavelength was verified to be linearly dependent on the position, providing a linearity beyond 99%. The proposed LVCF will thus be actively utilized in a portable micro-spectrometer and spectral scanning device.National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIP) (No. 2016R1A2B2010170); ARC Future Fellowship FT110100853

Purification of Sulfhydryl Oxidase from Human Foreskin Tissue and Immunohistochemical Localization

Human sulfhydryl oxidase, catalyzing the conversion of either free or bound thiol to disulfide compound, was isolated from human skin tissue to apparent homogeneity through multiple steps of ammonium sulfate salting-out, DEAE-cellulose chromatography, CM-cellulose chromatography and ACA54 gel filtration. The enzyme was shown to have a molecular weight of 65 kDa and a specific activity of 8.39 x 103 Ufmg protein. The specific polyclonal antibody was raised, with which the tissue distribution of the enzyme was studied immunohistochemically. The enzyme is present ubiquitously in most human tissues. However, the granular layer of the epidermis, stromal tissues of the breast and uterine cervix, hepatocytes and islets of the pancreas are noted to contain a comparatively high amount of the enzyme

Structural color filters based on an all-dielectric metasurface exploiting silicon-rich silicon nitride nanodisks

An all-dielectric metasurface is deemed to serve a potential platform to demonstrate spectral filters. Silicon-rich silicon nitride (SRN), which contains a relatively large portion of silicon, can exhibit higher refractive indices, when compared to silicon nitride. Meanwhile, the extinction coefficient of SRN is smaller than that of hydrogenated amorphous silicon, leading to reduced absorption loss in the shorter wavelength. SRN is therefore recommended as a scattering element from the perspective of realizing all-dielectric metasurfaces. In this work, we propose and embody a suite of highly efficient structural color filters, capitalizing on a dielectric metasurface that consists of a two-dimensional array of SRN nanodisks that are embedded in a polymeric layer. The SRN nanodisks may support the electric dipole (ED) and magnetic dipole (MD) resonances via Mie scattering, thereby leading to appropriate spectral filtering characteristics. The ED and MD are identified from field profile observation with the assistance of finite-difference time-domain simulations. The manufactured color filters are observed to produce various colors in both transmission and reflection modes throughout the visible band, giving rise to a high transmission of around 90% in the off-resonance region and a reflection ranging up to 60%. A variety of colors can be realized by tuning the resonance by adjusting the structural parameters such as the period, diameter, and height of the SRN nanodisks. The spectral position of resonances might be flexibly tuned by tailoring the polymer surrounding the SRN nanodisks. It is anticipated that the proposed coloring devices will be actively used for color displays, imaging devices, and photorealistic color printing.National Research Foundation of Korea (NRF) funded by the Korean government (No.2016R1A2B2010170 and 2018R1A6A1A03025242); Australian Research Council Future Fellowship (FT110100853, Dr. Duk-Yong Choi)

Rayleigh-Schroedinger-Goldstone variational perturbation theory for many fermion systems

We present a Rayleigh-Schroedinger-Goldstone perturbation formalism for many fermion systems. Based on this formalism, variational perturbation scheme which goes beyond the Gaussian approximation is developed. In order to go beyond the Gaussian approximation, we identify a parent Hamiltonian which has an effective Gaussian vacuum as a variational solution and carry out further perturbation with respect to the renormalized interaction using Goldstone's expansion. Perturbation rules for the ground state wavefunctional and energy are found. Useful commuting relations between operators and the Gaussian wavefunctional are also found, which could reduce the calculational efforts substantially. As examples, we calculate the first order correction to the Gaussian wavefunctional and the second order correction to the ground state of an electron gas system with the Yukawa-type interaction.Comment: 11pages, 1figur

Revealing salt-expedited reduction mechanism for hollow silicon microsphere formation in bi-functional halide melts

The thermochemical reduction of silica to silicon using chemical reductants requires high temperature and has a high activation energy, which depends on the melting temperature of the reductant. The addition of bi-functional molten salts with a low melting temperature may reduce the required energy, and several examples using molten salts have been demonstrated. Here we study the mechanism of reduction of silica in the presence of aluminum metal reductant and aluminum chloride as bi-functional molten salts. An aluminum-aluminum chloride complex plays a key role in the reduction mechanism, reacting with the oxygen of the silica surfaces to lower the heat of reaction and subsequently survives a recycling step in the reaction. This experimentally and theoretically validated reaction mechanism may open a new pathway using bi-functional molten salts. Furthermore, the as-synthesized hollow porous silicon microsphere anodes show structural durability on cycling in both half/full cell tests, attributed to the high volume-accommodating ability