137 research outputs found
Performance analysis of the WiNC2R platform:
No full textA Cognitive Radio (CR) is an intelligent transceiver device, able to support multiple technologies, dynamic re-configurability, ease of programming and collaboration with other CR devices to improve the communication efficiency. The two key requirements for an efficient CR implementation are flexibility in operation/programming and speed.
WiNC2R (Winlab Network Centric Cognitive Radio) achieves high speed of operation using its hardware platform and flexibility using its software-configurable architecture. The current WiNC2R architecture implements an 802.11a-like OFDM flow. We evaluate the WiNC2R hardware architecture to see the modularity in the architecture, separation of data and control flow and the performance in terms of latency and throughput. To test the system, the Xilinx Bus Functional Model environment, which is designed to test the IBM standard bus-architecture-based hardware systems, is used. We use a simple ALOHA protocol in the MAC layer to communicate between two WiNC2R nodes and evaluate the performance under the best-case scenario, where the performance is only hindered by the architecture itself rather than external conditions like channel state.
The results of our basic experiments showed that for a single OFDM 802.11a-like flow, the Unit Control Modules (UCM) were idle for almost 80% of the total processing time.
We then tested the WiNC2R system to study the effects of changing the frame size. It was seen that the latencies in the WiNC2R transmitter are frame-size dependent while those in the receiver mainly depend on the size of the data in the last chunk rather than the size of the whole frame. We suggest that chunk size should be 2 OFDM symbols, and chunking be moved to MAC layer for better performance. We give analytical estimates of resulting performance improvement. In the next experiment, we describe virtualization in the WiNC2R by adding more flows. We describe the steps to implement the additional flows and estimate maximum number of concurrent flows possible.
In the last analysis, we show the effect of operating clock frequency on the performance. We prove that at 250 MHz operating frequency and 2 OFDM symbols per chunk, the current WiNC2R implementation will be able to satisfy the SIFS criterion.M.S.Includes bibliographical references (p. 72-73)by Sumit Satarka
Query optimization in mobile environments
No full textWe consider the issue of optimizing queries for distributed processing in mobile environment. An interesting characteristic of mobile machines is that they depend on battery as a source of energy which may not be substantial enough. Hence, the appropriate optimization criterion in a mobile environment considers both resource utilization and energy consum- ption at the mobile client.
In this scenario, the optimal plan for a query depends on the residual battery level of the mobile client and the load at the server. We approach this problem by compiling a query into a sequence of candidate plans, such that for any state of the client-server system, the optimal plan is one of the candidate plans.
A general solution is proposed by adapting the partial order dynamic programming search algorithm (p.o dp) such that the coverset of the query is the set of candidate plans. We propose two novel algorithms, namely, the linear combinations algorithm and the linearset algorithm (referred to as the linear algorithms) that compute the linearset of a query. The linear- set of a query is an approximation to the coverset returned by p.o. dp.
We show, by means of simulation, that (1) the linearset is an excellent approximation of the coverset, (2) query compilation using the linear algorithms outperform query compilation using p.o. dp by factors ranging from 2 to 9, (3) the time taken to compile queries using the linear algorithms for the general optimization criterion is at most twice the time taken by a System R* like standard query optimizer search algorithm, and (4) the run time overhead incurred by the linear algorithms technique is minimal.
The techniques presented in the paper are of general applicability to multi-criterion optimization problems in distributed databases, where each criterion is an additive metric.Technical report lcsr-tr-21
Interactive machine learning for complex graphics selection
No full textThesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2016.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 89-91).Modern vector graphics editors support the creation of a wonderful variety of complex designs and artwork. Users produce highly realistic illustrations, stylized representational art, even nuanced data visualizations. In light of these complex graphics, selections, representations of sets of objects that users want to manipulate, become more complex as well. Direct manipulation tools that artists and designers find accessible and useful for editing graphics such as logos and icons do not have the same applicability in these more complex cases. Given that selection is the first step for nearly all editing in graphics, it is important to enable artists and designers to express these complex selections. This thesis explores the use of interactive machine learning techniques to improve direct selection interfaces. To investigate this approach, I created Insight, an interactive machine learning selection tool for making a relevant class of complex selections: visually similar objects. To make a selection, users iteratively provide examples of selection objects by clicking on them in the graphic. Insight infers a selection from the examples at each step, allowing users to quickly understand results of actions and reactively shape the complex selection. The interaction resembles the direct manipulation interactions artists and designers have found accessible, while helping express complex selections by inferring many parameter changes from simple actions. I evaluated Insight in a user study of digital designers and artists, finding that Insight enabled users to effectively and easily make complex selections not supported by state-of-the-art vector graphics editors. My results contribute to existing work by both indicating a useful approach for providing complex representation access to artists and designers, and showing a new application for interactive machine learning.by Sumit Gogia.M. Eng
Optimizing queries for coarse grain parallelism
No full textWe consider the problem of optimizing select-project-join relational queries for minimum response time on parallel machines. The design of the optimizer is based on three ideas: (1) the concept and quantification of degree of coarse grain parallelism for an execution tree, (2) the design of a parallelizing scheduler for a tree of coarse grain operations which is provably near optimal, and (3) the analysis of the scheduling algorithm to obtain a cost formula for parallel execution time. The search algorithm of the optimizer is presented as a multi-dimensional dynamic programming algorithm. We present two three- dimensional search algorithms for the case when placement of relations in the parallel machine do not overlap. We propose the tree placement strategy and demonstrate, by means of examples, how the number of dimensions in the search can be significantly reduced, thereby increasing the efficiency of the search algorithm.Technical report lcsr-tr-21
Redox-Responsive Nanocapsules for the Spatiotemporal Release of Miltefosine in Lysosome: Protection against Leishmania
No full textLeishmaniasis, a vector-borne disease, is caused by intracellular parasite Leishmania donovani. Unlike most intracellular pathogens, Leishmania donovani are lodged in parasitophorous vacuoles and replicate within the phagolysosomes in macrophages. Effective vaccines against this disease are still under development, while the efficacy of the available drugs is being questioned owing to the toxicity for nonspecific distribution in human physiology and the reported drug-resistance developed by Leishmania donovani. Thus, a stimuli-responsive nanocarrier that allows specific localization and release of the drug in the lysosome has been highly sought after for addressing two crucial issues, lower drug toxicity and a higher drug efficacy. We report here a unique lysosome targeting polymeric nanocapsules, formed via inverse mini-emulsion technique, for stimuli-responsive release of the drug miltefosine in the lysosome of macrophage RAW 264.7 cell line. A benign polymeric backbone, with a disulfide bonding susceptible to an oxidative cleavage, is utilized for the organelle-specific release of miltefosine. Oxidative rupture of the disulfide bond is induced by intracellular glutathione (GSH) as an endogenous stimulus. Such a stimuli-responsive release of the drug miltefosine in the lysosome of macrophage RAW 264.7 cell line over a few hours helped in achieving an improved drug efficacy by 200 times as compared to pure miltefosine. Such a drug formulation could contribute to a new line of treatment for leishmaniasis.A. Das acknowledges SERB (India) Grants (CRG/2020/000492 and JCB/2017/000004) and DBT Grant (BT/PR22251/NNT/28/1274/2017) for supporting this research. N. Mukherjee acknowledges SERB (India) Grant PDF/2016/001437 and K. Das acknowledges the grant EMR/2015/001674 for supporting this research. Financial support from DST (DST/INSPIRE/03/2017/002477) is acknowledged by R.T. This manuscript bears CSMCRI registration no 7/2021.Pramanik, SK (corresponding author), CSIR Cent Salt & Marine Chem Res Inst, Bhavnagar 364002, Gujarat, India.
Mukherjee, N (corresponding author), CSIR Indian Inst Chem Biol, Canc Biol & Inflammatory Disorder Div, Kolkata 700032, India.
Chattopadhy, S (corresponding author), BITS Pilani, Pilani 403726, Goa, India.
Das, A (corresponding author), Indian Inst Sci Educ & Res Kolkata, Mohanpur 741246, W Bengal, India.
[email protected]; [email protected]; [email protected]
Fast search methods for biological sequence databases
No full textBiology researchers have a pressing need for data management technologies which will make the storage and retrieval of DNA and protein sequence data accurate and efficient. The volume of data generated by DNA sequencing is already massive and will continue to grow rapidly. Even if the current sequence databases are adequate today, they most assuredly will become inadequate in the future when far more sequence data has been determined. The direction of future research in sequence databases needs to be in the organization of information. This is so that the volume of data needing to be searched does not grow linearly with the volume of sequence data being discovered.
We propose to develop an index structure and retrieval system called PROXIMAL for biological sequence databases which promises to be efficient and general. This organization of the databases will complement other current efforts at sequence comparison and analysis, by providing an infrastructure in which other methods can be used to efficiently locate desired sequences. Our method relies on the use of reference strings to partition the database of sequences. It is efficient since the use of multiple reference strings for any given distance measure greatly reduces the number of sequences that must be examined, allowing us to quickly locate sequences based on a precomputed metric. It is general since multiple distance measures can be used. These include at least differing gap and mismatch weights for the basic edit distance calculation, or entirely different models of mutation. The only requirement is that there is a metric structure - mainly, that the calculations satisfy the triangle inequality. This is a weak requirement that is satisfied by many interesting measures, including those currently in wide use for sequence comparison.Technical report LCSR-TR-21
Heme-oxygenase-1 Induction Improves Type-1 Cardiorenal Syndrome Only In Mice With Impaired AngII-induced Lymphocyte Activation (SCID Mice)
No full textRational: The absence of lymphocyte activity protects SCID mice from AngII-induced hypertension facilitating blood pressure-induced sodium excretion, possibly via the stimulation of eNOS- and COX-2-dependent pathways. Type-1 cardiorenal syndrome (CRS-1), characterized by acute kidney dysfunction secondary to deterioration in cardiac function, is caused by renal arteriolar vasoconstriction, mediated by the activation of renin-angiotensin and sympathetic nervous systems (RAAS, SNS). Heme Oxygenase-1 (HO-1) induction improves renal function, but not renal vasoconstriction, in AngII-induced hypertension, and causes the desensitization of vascular smooth muscle to phenylephrine.
Objectives: We evaluated whether AngII resistant SCID mice develop CRS-1 as occurs in control mice, and the differential effects of HO1 induction on renal hemodynamics in CRS-1.
Methods: Post ischemic heart failure was induced in C57 and SCID mice by left anterior coronary artery ligation. Mice were divided in 4 groups: sham, myocardial infarction (MI), MI treated with cobalt protoporphyrin (CoPP), an inducer of HO-1, in the presence and absence of HO activity inhibitor, stannous mesoporphyrin (SnMP). All mice underwent echocardiography (ejection fraction, EF) and renal echoDoppler (arterial pulsatility index, K-PI) examination 30 days after surgery.
Results: EF was significantly reduced both in control and SCID mice after MI (C57: sham 0.60±0.07, MI 0.45±0.04, p<0.05; SCID: sham 0.60±0.06, MI: 0.46±0.1, p<0.01). K-PI was significantly increased in MI groups compared to sham groups (C57: sham 0.98±0.05, MI 1.12±0.11, p<0.05; SCID: sham 0.72±0.08, MI 1.37±0.37, p<0.05). HO1 induction improved renal vasoconstriction only in SCID mice (SCID K-PI: MI+CoPP 0.9±0.19 p<0.5çC57 K-PI: MI+CoPP 1.05±0.15, n.s.). In SCID mice SnMP reversed the effect of CoPP on renal vasoconstriction.
Conclusion: CRS-1 is similar in SCID and control mice and is associated with increased renal arterial resistance. HO-1 induction improves renal vasoconstriction only in SCID (AngII resistant) mice with CRS-1, suggesting that increased HO-1 activity cannot protect the kidney from AngII-induced lymphocyte activation, but only from SNS-induced vasoconstriction.
Author Disclosures: P. Pesce: None. D. Sacerdoti: None. S.R. Monu: None. K. Sodhi: None. M. Boldrin: None. N.G. Abraham: None.
Key Words: Angiotensin II • Renal circulation • Heart failur
FPU designs with NEM relays
No full textThesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2013.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (pages 71-74).Nano-electromechanical (NEM) relays are an alternative to CMOS transistors as the fabric of digital circuits. Circuits with NEM relays offer energy-efficiency benefits over CMOS since they have zero leakage power and are strategically designed to maintain throughput that is competitive with CMOS despite their slow actuation times. The floating-point unit (FPU) is the most complex arithmetic unit in a computational system. This thesis investigates if the energy-efficiency promise of NEM relays demonstrated before on smaller circuit blocks holds for complex computational structures such as the FPU. The energy, performance, and area trade-offs of FPU designs with NEM relays are examined and compared with that of state-of-the-art CMOS designs in an equivalent scaled process. Circuits that are critical path bottlenecks, including primarily the leading zero detector (LZD) and leading zero anticipator (LZA) blocks, are carefully identified and optimized for low latency and device count. We manage to drop the NEM relay FPU latency from 71 mechanical delays in a CMOS-style implementation to 16 mechanical delays in a NEM relay pass-logic style implementation. The FPU designed with NEM relays features 15x lower energy per operation compared to CMOS.by Sumit Dutta.S.M
Programmed exosome fusion for energy generation in living cells
No full text© 2021, The Author(s), under exclusive licence to Springer Nature Limited.Biological membrane-enclosed organelles are fascinating examples of spatially confined nanoreactors for biocatalytic transformations such as cascade reactions involving multiple enzymes; however, the fabrication of their synthetic mimics remains a considerable challenge. Here we demonstrate supramolecular chemistry-based bridging of two membranes leading to controlled fusion of exosomes that act as nanoreactors for effective biocatalytic cascades, with prolonged functionality inside of living cells. Exosome membrane proteins were chemically engineered with a catechol moiety to drive fusion by supramolecular complexation to bridge the membranes. This strategy successfully encapsulated multiple enzymes and assembled the minimal electron transport chain in the plasma membrane, leading to tuneable, enhanced catalytic cascade activity capable of ATP synthesis inside of tissue spheroids. This nanoreactor was functional for many hours after uptake into living cells, showed successful penetration into tissue spheroids and repaired the damaged region by supplying ATP, all of which represent an advance in the mimicking of nature’s own organelles. [Figure not available: see fulltext.].11Nsciescopu
Essays on impact of information technology
No full textThesis (Ph. D.)--Massachusetts Institute of Technology, Sloan School of Management, 2007.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references.The five essays in this dissertation look at how specific information technologies (such as Electronic Document Management (EDM), Semantic Web and RuleML) and IT in general can be used to automate and standardize data and processes, enable faster and more accurate information flow, and improve individual as well as firm performance. The first essay is an analytical review-type study in which we provide a comprehensive survey of research literature about different complementary organizational assets that when coupled with IT can lead to higher firm performance. In the second essay, we study the causal effects of digitizing work on information workers' time- use and performance at a large insurance firm. We make causal inferences and obtain unbiased estimates by exploiting a quasi-experiment: the phased introduction of Electronic Document Management (EDM) across multiple offices at different dates. In addition to large changes in time-use and performance, we find that digitization leads to a decline in the substitutable routine labor input and an increase in complementary non-routine cognitive labor input at the information worker level. We also uncover a new micro-level mechanism, "IT-enabled slack", that explains how exactly IT can lead to payoff in terms of information worker productivity. In the third essay, we examine the IT productivity relationship using a large primary source firm-level dataset about IT investments that spans the 2003-2005 period. Given results from previous studies, we present evidence of an inverted U-shaped returns curve, with returns now close to what they were in pre-Internet era. The fourth essay explores what high-performing firms specifically do to gain the greatest benefits from their IT investments.(cont.) Through a set of matched interviews with multiple respondents at 138 firms, we find that data/process standardization and systems integration, level of application integration and several IT-specific cultural elements are positively correlated with IT impact on customer satisfaction. The fifth essay shows the first detailed realistic e-business application scenario that exploits capabilities of the SweetRules V2.1 toolset for e-contracting using the SweetDeal approach. SweetRules is a powerful integrated set of tools for semantic web rules and ontologies. SweetDeal is a rule-based approach to representation of business contracts.by Sumit Milap Bhansali.Ph.D
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