VideoAcM: a transitive and temporal access control mechanism for collaborative video database production applications

Access control models play an important role in database management systems. In general, there are three basic access control models: Discretionary Access Control (DAC), Mandatory Access Control (MAC), and Non-Discretionary Access Control (NAC). Currently, the majority of commercial DBMSs provide only DAC, and some temporal access control models have been derived based on either DAC or NAC. In the context of video database applications, since the structure of video data is complex in nature, it requires a specific and tailor-made access control mechanism which should include MAC as well as DAC and NAC. However, only few efforts have been put on access control models for video database systems. In this paper, a transitive and temporal access control mechanism for collaborative video database production applications has been proposed, which subsumes the properties of DAC, MAC, and NAC. Moreover, our proposed mechanism is integrated with the intellectual property concerns by constructing an access control hierarchy of video data with authorization rules. In particular, our mechanism can derive novel authorization rules not only on conventional client-data access control, but also on data–data access control. Besides video data, the proposed model is applicable to other data types which exhibit a hierarchical data structure.     

Localized iterative generalized multipole technique for largetwo-dimensional scattering problems

We propose a novel and efficient solution for the generalized multipole technique (GMT): the localized iterative generalized multipole technique (LIGMT). In LIGMT, an analytic constraint is imposed on the power radiated by the set of multipole sources sharing the same origin, rendering it minimum over a given angular sector. In this way, the power radiated by each set of multipoles is confined to a different section of the scatterer surface. It follows that each set of multipole coefficients can be solved step by step via an iterative process, which circumvents the need to solve the large and full matrix equation. This implies a significant reduction of the computational and storage cost, enhancing the scope of application of the GMT method to larger problems     

Investigation on the volatile oil of Makó onions

The authors have developed a method for determining the volatile oil content of onions. Using this method they found in the Hungarian Makó onions 0.019—0.031 % volatile oil, depending on storage. The composition of onion oil was studied by GC; GC-MS and TLC methods. GC-MS revealed 20 volatile sulphur compounds identified as 10 trisulphides, 6 disulphides, 3 tetrasulphides, and 1 thiophene derivative as well as one unsaturated aldehyde. Three of these: ethyl cis-1-propenyl trisulphide, ethyl trans-1-propenyl trisulphide, and butyl methyl trisulphide were described for the first time in onions. Carbonyl compounds were studied in the form of derivatives obtained with 2,4-dinitrophenyl hydrazine. On the basis of Rf-values and by addition, propanal, butanal, pentanal and hexanal were identified in the aldehyde fraction, while in the dicarbonyl fraction — beside an unknown compound — glyoxal and methyl glyoxal were identified. The presence of these two compounds in onion oil has been reported for the first time.     

Rich Phase Behavior in a Supramolecular Conducting Material Derived from an Organogelator

Organic conducting fiber‐like materials hold great promise for the development of nanowires that can act as connections in miniature electronic devices, as an alternative to inorganic nanometer scale structures. This article presents a conducting organic tetrathiafulvalene‐based supramolecular material which possesses a rich phase behavior with different packing of the molecules in the different forms, evidenced by electron spin resonance (ESR) spectroscopy. The distinct phases of conducting nanofibers can be easily fabricated through the temperature control of their preparation process from a xerogel by doping with iodine vapors. A total of four conducting phases have been identified conclusively using ESR spectroscopy as the key analytical tool. Three of the phases show a good long‐term stability and areas in which the I–V curves have ohmic behavior when studied by current sensing (conducting) AFM. They offer promise for applications where electrical nanometer scale connections are required.     

Comparison of extraction methods for the isolation of volatile compounds from distilled alcoholic beverages

Batch and continuous solvent extraction methods were evaluated, using an alcoholic model system, to select the best alternative for the isolation of volatile aroma compounds from distilled alcoholic beverages. Recoveries using pentane, pentane-diethyl ether (2:1) and dichloromethane were compared. Pentane extraction produced the best results, particularly by a continuous procedure for 6 h.     

Domiciliary oxygen therapy. Study of use in a rural area

OBJECTIVE: To assess use of long-term oxygen therapy (LTOT) in a rural community we conducted a transversal study. METHOD: Data was collected in patients' homes, and based on the total number of patients with LTOT, with reference to indication, follow-up and correct completion; two oximetries were carried out, breathing room air, and after breathing oxygen. Of the 70 patients with LTOT, 7 were considered not eligible, the prevalence was found to be: 179/100,000 inhabitants. Sixteen patients were excluded, 6 with exacerbation, and 10 who were unable to be contacted at their home address. The sample was composed of 45 patients. The most frequent diagnosis was COPD (34/45). Indication of LTOT was carried out in the hospital in 40 (89%) patients, and in the health centre in 5 (11%). RESULTS: In 22 (49%) the treatment could be considered acceptable, and only in 21 (46%), the indication of LTOT was correct. Oxygen was administered at least 15 hours/day in 42% of cases (19/45). Patients with periodical check-ups, maintained better pharmacological treatment, although there were no significant differences in the carrying out of LTOT. Using oximetry, it was shown that in 27 patients the SaO2 was lesser than or equal to 88%, and that in 23 cases (85%) administration of oxygen, corrected the saturation. Only in 11 (24%) the indication criteria and adequate administration of LTOT were carried out, as well as correction of the hypoxemia following administration of oxygen. CONCLUSIONS: The prevalence was found to be very high. The results show this form of treatment as being very badly controlled. In a rural community, the pulse oximetry is useful in the follow-up of TLOT.     

A novel geometry for circular series connected multilevel inductorsfor CMOS RF integrated circuits

The scope of this brief is to introduce a novel geometry for circular series connected multilevel inductors. The idea is to improve the overlapping of the different metal layers that form the integrated inductor to maximize the magnetic flux shared by them and so the inductance. The performance of this new geometry has been compared with the conventional one, using Agilent HFSS field solver. After that, two multilevel inductors using this new geometry have been fabricated in a standard 0.6 μm three-metal CMOS process and measured     

Spectral acceleration of the generalized forward-backward method

The generalized forward-backward (GFB) method was introduced as an iterative method of moments solution to compute the electromagnetic scattering from targets on ocean-like rough surfaces. In this paper, an existing spectral acceleration algorithm is adapted to the GFB. The spectral acceleration is presented for both polarizations and for perfect electrically conducting (PEC) and non-PEC surfaces. The accelerated scheme reduces the computational scaling cost of the GFB from O(N²) to O(N) per iteration as the length of the sea surface increases linearly with the number of unknowns N. The numerical results demonstrate that the spectral acceleration introduces negligible error while greatly improving the efficiency of the GFB method     

Synthesis of a geostationary antenna with eight independently variable beams

We describe the process by which this antenna synthesis problem was tackled, given certain hardware possibilities and beam specifications.