Study of Impact of Dispersion of Gases From Stack on Environment Through CFD Simulation

The main objective is to analyse the dispersion of gases emitted under different conditions of mass flow rate at the exit and ambient crossflow velocity by using software ANSYS. Main focus id to find out whether designed boiler stack can disperse atmospheric pollutants away from city or surroundings where the boiler is installed. Dispersion modelling includes means of calculating ambient ground level concentrations of emitted substances, considering the information like meteor ological data, pollutants flow rates and terrain data of area. This modelling is done to assess that the Ground level concentrations (GLC) of atmospheric pollutants owing to emissions from boiler stack are less than applicable ambient air quality standard

AdSplit: Separating smartphone advertising from applications

A wide variety of smartphone applications today rely on third-party advertising services, which provide libraries that are linked into the hosting application. This situation is undesirable for both the application author and the advertiser. Advertising libraries require additional permissions, resulting in additional permission requests to users. Likewise, a malicious application could simulate the behavior of the advertising library, forging the user's interaction and effectively stealing money from the advertiser. This paper describes AdSplit, where we extended Android to allow an application and its advertising to run as separate processes, under separate user-ids, eliminating the need for applications to request permissions on behalf of their advertising libraries. We also leverage mechanisms from Quire to allow the remote server to validate the authenticity of client-side behavior. In this paper, we quantify the degree of permission bloat caused by advertising, with a study of thousands of downloaded apps. AdSplit automatically recompiles apps to extract their ad services, and we measure minimal runtime overhead. We also observe that most ad libraries just embed an HTML widget within and describe how AdSplit can be designed with this in mind to avoid any need for ads to have native code

Physics-Guided Abnormal Trajectory Gap Detection

Given trajectories with gaps (i.e., missing data), we investigate algorithms to identify abnormal gaps in trajectories which occur when a given moving object did not report its location, but other moving objects in the same geographic region periodically did. The problem is important due to its societal applications, such as improving maritime safety and regulatory enforcement for global security concerns such as illegal fishing, illegal oil transfers, and trans-shipments. The problem is challenging due to the difficulty of bounding the possible locations of the moving object during a trajectory gap, and the very high computational cost of detecting gaps in such a large volume of location data. The current literature on anomalous trajectory detection assumes linear interpolation within gaps, which may not be able to detect abnormal gaps since objects within a given region may have traveled away from their shortest path. In preliminary work, we introduced an abnormal gap measure that uses a classical space-time prism model to bound an object's possible movement during the trajectory gap and provided a scalable memoized gap detection algorithm (Memo-AGD). In this paper, we propose a Space Time-Aware Gap Detection (STAGD) approach to leverage space-time indexing and merging of trajectory gaps. We also incorporate a Dynamic Region Merge-based (DRM) approach to efficiently compute gap abnormality scores. We provide theoretical proofs that both algorithms are correct and complete and also provide analysis of asymptotic time complexity. Experimental results on synthetic and real-world maritime trajectory data show that the proposed approach substantially improves computation time over the baseline technique

Local Co-location Pattern Detection: A Summary of Results

Given a set of spatial objects of different features (e.g., mall, hospital) and a spatial relation (e.g., geographic proximity), the problem of local co-location pattern detection (LCPD) pairs co-location patterns and localities such that the co-location patterns tend to exist inside the paired localities. A co-location pattern is a set of spatial features, the objects of which are often related to each other. Local co-location patterns are common in many fields, such as public security, and public health. For example, assault crimes and drunk driving events co-locate near bars. The problem is computationally challenging because of the exponential number of potential co-location patterns and candidate localities. The related work applies data-unaware or clustering heuristics to partition the study area, which results in incomplete enumeration of possible localities. In this study, we formally defined the LCPD problem where the candidate locality was defined using minimum orthogonal bounding rectangles (MOBRs). Then, we proposed a Quadruplet & Grid Filter-Refine (QGFR) algorithm that leveraged an MOBR enumeration lemma, and a novel upper bound on the participation index to efficiently prune the search space. The experimental evaluation showed that the QGFR algorithm reduced the computation cost substantially. One case study using the North American Atlas-Hydrography and U.S. Major City Datasets was conducted to discover local co-location patterns which would be missed if the entire dataset was analyzed or methods proposed by the related work were applied

Separating Smartphone advertising from applications

A wide variety of smartphone applications today rely on third-party advertising services, which provide libraries that are linked into the hosting application. This situation is undesirable for both the application author and the advertiser. Advertising libraries require additional permissions, resulting in additional permission requests to users. Likewise, a malicious application could simulate the behavior of the advertising library, forging the user's interaction and effectively stealing money from the advertiser. This thesis describes AdSplit, where we extended Android to allow an application and its advertising to run as separate processes, under separate user-ids, eliminating the need for applications to request permissions on behalf of their advertising libraries. We also leverage mechanisms from QUIRE to allow the remote server to validate the authenticity of client-side behavior. In this thesis, we quantify the degree of permission bloat caused by advertising, with a study of thousands of downloaded apps. AdSplit automatically recompiles apps to extract their ad services, and we measure minimal runtime overhead. We also observe that most ad libraries just embed an HTML widget within and describe how AdSplit can be designed with this in mind to avoid any need for ads to have native code

CFD analysis of heat transfer in a helical coil heat exchanger using fluent

This thesis focuses on the CFD analysis of flow of fluid through a helical coil heat exchanger. Also on the enhancement in convective heat transfer in between the fluid and the surrounding surface in these helical coils which has been a major topic of study as reported by many researchers. As helical coil have compact size and higher heat transfer coefficient they are widely used in industrial applications such as power generation, nuclear industry, process plant, refrigeration, food industry, etc. In this study, an attempt has been made to study the parallel flow and counter flow of inner hot fluid flow and outer cold fluid flow, which are separated by copper surface in a helical coil heat exchanger. The temperature contours, velocity vectors, total pressure contours, total heat dissipation rate from the wall of the tube were calculated and plotted using ANSYS 13.0. Copper was used as the base metal for the inner and outer pipe and the fluid was taken as hot water for inner flow and cold water for outer flow

Simulation of an Adsorption Column for The Removal of Ethyl Acetate From Air

Adsorption of a toxic VOC, ethyl acetate is studied. The adsorbent used for this study is granular activated carbon. The adsorption isotherms are obtained at four distinct temperatures of 30, 35, 45, and 55o C. The physical properties of the adsorbent is provided by E-merck India. The Langmuir parameters and other data required in the simulations for this study are taken from Manjare & Ghoshal [2] [13]. The results are in agreement with that provided in Manjare & Ghoshal. The equation of state chosen for the modelling is Peng-Robinson equation of state and the momentum balance equation used is Ergun equation, best suited for both laminar and turbulent flow. The assumptions made while developing the mathematical model of the adsorption process include adiabatic and isothermal processes. The driving force is assumed to be linear. Results show that the isotherm best checks with the Langmuir isotherm model. The saturation capacity of the activated carbon varies from 0.73 to 0.487 kg/kg. The molecular diffusivity of the components is of the order of 10-6 m2/

Quire: Lightweight Provenance for Smart Phone Operating Systems

Smartphone apps often run with full privileges to access the network and sensitive local resources, making it difficult for remote systems to have any trust in the provenance of network connections they receive. Even within the phone, different apps with different privileges can communicate with one another, allowing one app to trick another into improperly exercising its privileges (a Confused Deputy attack). In Quire, we engineered two new security mechanisms into Android to address these issues. First, we track the call chain of IPCs, allowing an app the choice of operating with the diminished privileges of its callers or to act explicitly on its own behalf. Second, a lightweight signature scheme allows any app to create a signed statement that can be verified anywhere inside the phone. Both of these mechanisms are reflected in network RPCs, allowing remote systems visibility into the state of the phone when an RPC is made. We demonstrate the usefulness of Quire with two example applications. We built an advertising service, running distinctly from the app which wants to display ads, which can validate clicks passed to it from its host. We also built a payment service, allowing an app to issue a request which the payment service validates with the user. An app cannot not forge a payment request by directly connecting to the remote server, nor can the local payment service tamper with the request