Distance Preserving Graph Simplification

Large graphs are difficult to represent, visualize, and understand. In this paper, we introduce "gate graph" - a new approach to perform graph simplification. A gate graph provides a simplified topological view of the original graph. Specifically, we construct a gate graph from a large graph so that for any "non-local" vertex pair (distance higher than some threshold) in the original graph, their shortest-path distance can be recovered by consecutive "local" walks through the gate vertices in the gate graph. We perform a theoretical investigation on the gate-vertex set discovery problem. We characterize its computational complexity and reveal the upper bound of minimum gate-vertex set using VC-dimension theory. We propose an efficient mining algorithm to discover a gate-vertex set with guaranteed logarithmic bound. We further present a fast technique for pruning redundant edges in a gate graph. The detailed experimental results using both real and synthetic graphs demonstrate the effectiveness and efficiency of our approach.Comment: A short version of this paper will be published for ICDM'11, December 201

Opposite effects of lithium and valproic acid on trophic deprivation-induced GSK-3(Beta) activation, c-Jun expression and neuronal cell death

Recent studies demonstrate that lithium and valproic acid (VPA), two commonly used mood-stabilizing drugs, have neuroprotective effects against a variety of insults. Inhibition of the pro-apoptotic enzyme, glycogen synthase kinase-3P (GSK-3P), was suggested to be the mechanism of action of neuroprotection for both drugs. In this study, we tested if lithium and VPA could protect cultured cerebellar granule neurons (CGNs) from GSK-3P-mediated apoptosis induced by trophic withdrawal (serum/potassium deprivation). Lithium concentration-dependently (1-20 mM) protected CGNs. Indirubin, a specific, direct GSK-3P inhibitor, was also neuroprotective. On the contrary, VPA (1- 20 mM) did not provide any neuroprotection and even potentiated cell death. Immunoblot analysis revealed that lithium inhibited the trophic deprivation-induced activation of GSK-3P as well as the in vivo phosphorylation of Tau on Serl99, an exclusive target site for GSK-3p. Quite the opposite, VPA did neither inhibit GSK-3P activation nor hinder GSK-3p-mediated Tau phosphorylation. Besides GSK-3P activation, induction of the c- Jun stress response is also essential for apoptosis initiation in trophic deprived CGNs. Therefore we examined the effects of lithium and VPA on c-Jun expression following serum/potassium withdrawal. In accordance with the neuronal survival, lithium prevented the high increase in c-Jun expression, whereas VPA further elevated it. Altogether, our results show that VPA, unlike the common belief, is not a GSK-3 inhibitor and does not provide neuroprotection against GSK-3 P-mediated apoptosis

Perceptions on the Status of Lean-Manufacturing in Thermoplastics-Manufacturing Industry

The current study gathers thermoplastics professionals’ perceptions on the implementation of lean-manufacturing in the Thermoplastics-manufacturing industry through Qualtrics, which is a survey website. From the professionals’ perceptions, the current study infers the current status of lean-manufacturing implementation in the thermoplastic-manufacturing industry and identifies the best lean theories and tools for the industry. However, the results of the current study are not generalizable to the entire thermoplastic-manufacturing industry. The current study reviews thermoplastic-manufacturing processes from the house of lean’s perspective. The foundations of the house are stability and standardization, the pillars are Just-In-Time (JIT) and Jidoka, the roof is customer focus, and the heart is employee involvement. Thermoplastic-manufacturing processes include extrusion, fiber spinning, film casting, film blowing, and injection molding. The questionnaire of this survey includes six rating-scale, two multiple-choice (multiple-answer), and three closed-ended questions. The questionnaire was distributed to the respondents through email, LinkedIn, and Society of Plastic Engineers (SPE). The expected responses’ quantity was 35. Since some of the respondents did not complete the whole survey, the actual responses’ quantity for each question was between 39 and 45. Based on the respondents’ perceptions, the implementation of lean manufacturing in the thermoplastic-manufacturing industry is incomplete. The industry professionals should put more attention and effort on the implementation of JIT and Jidoka. To fully implement JIT and Jidoka, thermoplastic-manufacturing companies should use lean tools that are related to JIT and Jidoka, such as kanban, takt time, heijunka, Value Stream Mapping (VSM), and poka-yoke, more often. Additionally, the thermoplasticmanufacturing industry practitioners perceived that the best lean theories for the industry were standardization, involvement, and stability, and the best lean tools were 5S, Total Production Maintenance (TPM), and poka-yok

FishEYE: A Forensic Tool for the Visualization of Change-Over-Time in Windows VSS

For the digital forensic examiner, being able to perceive change-over-time supports the goal of being able to explain what happened. In our thesis, we focus on the improvements brought to digital forensic analysis by the visualization of forensic data and its application to digital forensic data that records change-over-time, specifically for a directory-tree structure and its content. By perceiving digital evidence visually, investigators are able to speed up the forensic analysis process, and at the same time better comprehend new unique relationships between data as well as more easily comprehend it in terms of its global context. To provide multiple snapshots of a directory-tree structure, we chose to utilize Shadow Copy (also known as Volume Snapshot Servie or Volume Shadow Copy Service or VSS), a technology included in Microsoft Windows which allows for the taking of manual or automatic backup copies or snapshots of data (including whole volumes) over regular intervals. VSS was chosen since it is a potential gold mine of forensic information, having been included in every version of Microsoft Windows since Windows XP. In this thesis, we propose and develop a tool to take advantage of the information contained within VSS by applying the fisheye focus+context visualization approach to the directory tree structure, with a series of segmented boxes for each to represent change-over-time for each directory/file, accomplishing our goal of providing investigators a clear picture of how a directory-tree structure has changed over time at a glance

Non-Relativistic Limit of Dirac Equations in Gravitational Field and Quantum Effects of Gravity

Based on unified theory of electromagnetic interactions and gravitational interactions, the non-relativistic limit of the equation of motion of a charged Dirac particle in gravitational field is studied. From the Schrodinger equation obtained from this non-relativistic limit, we could see that the classical Newtonian gravitational potential appears as a part of the potential in the Schrodinger equation, which can explain the gravitational phase effects found in COW experiments. And because of this Newtonian gravitational potential, a quantum particle in earth's gravitational field may form a gravitationally bound quantized state, which had already been detected in experiments. Three different kinds of phase effects related to gravitational interactions are discussed in this paper, and these phase effects should be observable in some astrophysical processes. Besides, there exists direct coupling between gravitomagnetic field and quantum spin, radiation caused by this coupling can be used to directly determine the gravitomagnetic field on the surface of a star.Comment: 12 pages, no figur