Victor N. Zakharov

Eustatic Curve for the Middle Jurassic--Cretaceous Based on Russian Platform and Siberian Stratigraphy: Zonal Resolution

We have used the stratigraphy of the central part of the Russian platform and surrounding regions to construct a calibrated eustatic curve for the Bajocian through the Santonian. The study area is centrally located in the large Eurasian continental craton, and was covered by shallow seas during much of the Jurassic and Cretaceous. The geographic setting was a very low-gradient ramp that was repeatedly flooded and exposed. Analysis of stratal geometry of the region suggests tectonic stability throughout most of Mesozoic marine deposition. The paleogeography of the region led to extremely low rates of sediment influx. As a result, accommodation potential was limited and is interpreted to have been determined primarily by eustatic variations. The central part of the Russian latform thus provides a useful frame of reference for the quantification of eustatic variations throughout the Jurassic and Cretaceous. The biostratigraphy of the Russian platform provides the basis for reliably determining age and eustatic events. The Mesozoic section of the central part of the Russian platform is characterized by numerous hiatuses. In this study, we filled the sediment gaps left by unconformities in the central part of the Russian platform with data from stratigraphic information from the more continuous stratigraphy of the neighboring subsiding regions, such as northern Siberia. Although these sections reflect subsidence, the time scale of variations in subsidence rate is probably long relative to the duration of the stratigraphic gaps to be filled, so the subsidence rate can be calculated and filtered from the stratigraphic data. We thus have compiled a more complete eustatic curve than would be p ssible on the basis of Russian platform stratigraphy alone. Relative sea level curves were generated by backstripping stratigraphic data from well and outcrop sections distributed throughout the central part of the Russian platform. For determining paleowater depth, we developed a model specifically designed for this region based on paleoecology, sedimentology, geochemistry, and paleogeography. The curve describes a series of high-frequency eustatic events superimposed on longer term trends. Many of the events identified from our study can be correlated to those found by Haq et al. (1988) and other sea level studies from other parts of the world, but there are significant differences in the relative magnitudes of events. Because the eustatic curve resulting from this study is based on a stable reference frame, the curve can be used in sedimentary basin modeling and as a tool for quantifying subsidence history from the stratigraphy of passive margins, basins, and other active regions.

Optical solver of combinatorial problems: nanotechnological approach

We present an optical computing system to solve NP-hard problems. As nano-optical computing is a promising venue for the next generation of computers performing parallel computations, we investigate the application of submicron, or even subwavelength, computing device designs. The system utilizes a setup of exponential sized masks with exponential space complexity produced in polynomial time preprocessing. The masks are later used to solve the problem in polynomial time. The size of the masks is reduced to nanoscaled density. Simulations were done to choose a proper design, and actual implementations show the feasibility of such a system.

Quasi-delay-insensitive computing device: methodological aspects and practical implementation

The approaches to self-timed hardware design are presented. The conditions of intersystem integration of synchronous and self-timed devices are considered through the example of the quasi-delay-insensitive computing device development. This device performs functions of division and square root extraction. It operates with numbers of single and double precisions corresponding to the IEEE 754 standard.

Late Jurassic/Early Cretaceous phosphates of Nordvik, North Siberian Basin

Late Jurassic and Early Cretaceous calcite-rich phosphate (fluor/hydroxy apatite) concretions in the North Siberian basin (Nordvik) have been analysed. Their mineralogical and geochemical (major, trace and rare earth element) characteristics are presented in a sedimentological context. Low oxygen conditions prevailed along large parts of the seafloor of this wide epicontinental sea. In the Nordvik region this, in combination with slow and very fine-grained clastic sedimentation, and high algal production, resulted in the formation of phosphatic concretions. The concretions mainly consist of microcrystalline to ultracrystalline apatite and calcite, with traces of sphalerite, pyrite, kaolinite, quartz and albite. The clastic composition of the concretions is comparable with the surrounding Nordvik shales. Dysoxic–anoxic conditions in the last precipitating pore-water phases (early diagenetic) are reflected in enrichments in, for example, vanadium, uranium and the rare earth elements in the concretions.

Speed-independent floating point coprocessor

Speed-independent fused multiply-add unit as a coprocessor is represented. It purely conforms to IEEE 754 Standard. For minimization hardware and power consumption, a number of pipeline stages is reduced down to two. Wallace tree in the multiplier utilizes redundant self-timed code. Represented unit is developed on a base of standard 65-nm CMOS bulk process. It provides a performance up to 0.54 Gflops, and power consumption at level of 450 m W/Gflops.

Brief Announcement: Graph-Based and Probabilistic Discrete Models Used in Detection of Malicious Attacks.

Design of program secure systems is connected with choice of mathematical models of the systems. A widely-used approach to malware detection (or classification as “benign-malicious”) is based on the system calls traces similarity measurement. Presently both the set-theoretical metrics (for example, Jaccard similarity, the Edit (Levenshtein) distance (ED) [1]) between the traces of system calls and the Markov chain based models of attack effect are used. Jaccard similarity is used when the traces are considered as a non-ordering set. The Edit Distance, namely, the minimal number of edit operations (delete, insert and substitute of a single symbol) required to convert one sequence to the other, is used as it reflects the traces ordering and semantics. However, the time and space complexity of the edit distance between two strings requires quadratic (in symbol numbers) complexity [1]. The traces can also be represented as a system calls graphs [2], the nodes of which are the system calls (or the items of the q-grams [1]). That is, we can consider the traces description by the ordered string as a partial case of the graph representation, for which it is possible to use the same similarity metrics with the same computational complexity.

Brief Announcement: A Technique for Software Robustness Analysis in Systems Exposed to Transient Faults and Attacks

At present, the problem of accounting of possible failures effect that can occur in the program memory area both due to some physical effects and some malicious attacks, and can distort values of variables, operations, the codes, etc., is solved by applying the widely used Fault Injection (FI) simulation technique. Main drawback of the FI is necessity to have different expensive software that can not be used to solve other design problems, in particular verification and testing.

Speed-independent fused multiply add and subtract unit

Speed-independent fused multiply-add-subtract unit is offered together with test environment providing full verification of its performance and workability in all range of the environment conditions. It complies with IEEE 754 Standard, and performs double and single precision operations at three operands. The unit is implemented as a two-channel with a common input and output. Each channel is a pipeline with four stages. Multiplier is implemented on the modified Booth algorithm using self-timed redundant code. The unit was designed on a base of standard CMOS process with 65 nm design rules and has 3.15 Gigaflops performance and less than 2 ns latency.

Clustering of Goods and User Profiles for Personalizing in E-commerce Recommender Systems Based on Real Implicit Data

The work is devoted to description of a hybrid approach to the preparation of data for electronic commerce recommender systems. The efficiency of recommendations is improved via use of various algorithms depending on what is known about the user, little or no information or it is not the first visit and the browsing history is available. In the first case our own Item-Item CF method is used enabling to solve the problem of cold start. In the second case our own method User-User CF is applied. Both methods are based on clustering of both explicit and implicit user data. This approach can increase the number of items in the basket in fewer clicks in comparison with the methods that do not use the implicit data. The approach applicability was confirmed via test on real data obtained from Thaisoap, an online store.

Functional approach in self-timed circuit design

Self-timed circuits have the unique properties of a lack of competition. One of the main problems of such circuits design - the analysis on self-timing (elements switching) and the construction of large circuits. In traditional approach computational complexity is so great, that it does not allow to analyze the most important practical circuits. In the functional approach we propose hierarchical method: on the lower level logic functions of elements are analyzed, on the top - the relationships between blocks. The complexity of calculations here is close to the linear function of the size of circuit. Such approach solves one of the main problems of self-timed circuits design - analysis circuits of any size. The efficiency of the proposed methods was confirmed by the developed SW.