Search

One of the core challenges in developing a computer system for machine learning is to make the system learn efficiently and effectively like a real human by grasping the domain knowledge exemplifie...

Abort-and-Restart model is used in Priority-based Functional Reactive Programming in which higher priority tasks can preempt lower priority tasks and the lower priority tasks are aborted and restarted after the higher priority tasks have finished execution. This paper discusses a potential of improving schedulability in P-FRP systems by using preemption threshold that it allows a task to only disable preemption of tasks up to a specified threshold priority. Also, a sufficient schedulability test condition is studied in this paper for P-FRP tasks using preemption threshold, which is a critical problem to be solved in order to explore the potential benefit.

Today is an era where multiprocessor technology plays a major role in designs of modern computer architecture. While multiprocessor systems offer extra computing power, it also opens a new range of...

Executing computing tasks with replications is an essential choice to achieve fault-tolerance in designing real-time, embedded systems. A problem of maximizing the number of real-time tasks with replications running on a multiprocessor embedded system is discussed in this letter. The partitioning problem can be modeled as a variant of the bin-packing problem. In the original problem, it is known that the first-fit (FF) method has a good worst-case performance bound of 4/3. Whether or not the same bound is achievable in the variant problem remains an open question. This letter closes the question by proving that the worst-case performance bound of using the FF method approaches to 2 but it never reaches it. Then, a tight bound of asymptotic worst-case performance is shown.

Representing an accurate model of how pulse waves are propagated and scattered in the vegetation is an interest in the area of wireless communications. Several research projects on this problem have supplied similar techniques using scalar transport theory when the incident, pulse waves have been altered to emulate a particular radiation condition in the real world. This paper will principally investigate a simulation model – a digital prototype that represents a physical problem – to correlate among these research projects that have tendencies of evolving progressively by facilitating a model-driven approach, thus establishing some of the computational models reliably. By providing summaries of these research projects, this paper has identified all commonalities and differences among these projects to delineate them into a simulation model, which is then divided into smaller submodels. These submodels are further validated to meet the minimum error criteria and conditions for better numerical res...

Harvesting energy for execution from the environment (e.g., solar, wind energy) has recently emerged as a feasible solution for low-cost and low-power distributed systems. When real-time responsiveness of a given application has to be guaranteed, the recharge rate of obtaining energy inevitably affects the task scheduling. This paper extends our previous works in (1) (2) to explore the real-time task assignment problem on an energy-harvesting distributed system. The solution using Ant Colony Optimization (ACO) and several significant improvements are presented. Simu- lations compare the performance of the approaches, which demonstrate the solutions effective- ness and efficiency.

Many modern workloads are a heterogeneous mix of parallel applications running on machines with complex processors and memory systems. These workloads often interfere with each other by contending for the limited set of resources in a machine, leading to performance degradation. In principle, one can use hardware performance counters to characterize the root causes of interference inside a modern machine. However, we show that current facilities in today's operating systems mean that such an analysis requires careful consideration of the intricacies of specific hardware counters, domain knowledge about the applications, and a deep understanding of the underlying hardware architecture. In contrast, we present the design of Glatt, which is able to automatically identify the root causes of interference in a machine online. Glatt can expose this information to a runtime or the operating system for predicting better thread assignments or for dynamically increasing/decreasing parallelism within each runtime.

A one-pot procedure for the synthesis of bicyclo[4.3.0]alkenols is described. Alkenylboranes, formed in situ by hydroboration, undergo stereoselective intramolecular Diels-Alder reactions to give alkylboranes, which upon oxidation, yield the products corresponding to endo addition.

In the past decades, many algorithms with the goal of achieving energy efficiency have been proposed for scheduling real-time tasks. Due to a lack of a unified testing framework, most of them were evaluated via simulations under their own experimental scenarios. However, finding their performance in real processors is essential if these algorithms are to be used in practice. In this paper, we design a unified framework to evaluate power-aware scheduling algorithms based on a real Intel PXA255 XScale processor, and present a case study to compare several key algorithms using DVS/Shut-Down. The energy efficiency and the quantitative difference in their performance as well as the practical issues found in the implementation of these algorithms are discussed. Our experiments show a gap between the theoretical results and the real results. Our framework not only gives researchers a tool to evaluate their system designs, but also helps them to bridge this gap in their future works.

A one-pot procedure for the synthesis of bicyclo[4.3.0]alkenols is described. Alkenylboranes, formed in situ by hydroboration, undergo stereoselective intramolecular Diels-Alder reactions to give alkylboranes, which upon oxidation, yield the products corresponding to endo addition.

One pot reaction of anilines, benzaldehydes and 2-pyrrolines under lanthanide triflate catalysis affords substituted hexahydropyrrolo[3,2-c]quinolines in good to excellent yields.

Real-time systems are one of the fields of computing where major benefits are expected from the increasing availability of multiprocessor technology. Heterogeneous computing environments, which utilize different high-performance machines interconnected via a high speed communication system, are well suited to the large, computation intensive, real-time or non-real-time applications. Nowadays, many of the systems in these environments are powered by rechargeable batteries. Scheduling real-time tasks on these rechargeable systems is an important issue which has been studied in the literatures. In this paper, we explore the task assignment problem on heterogeneous distributed system with rechargeable batteries. Our techniques to solve the problem are based on four heuristics, namely Minimum Schedule Length (MSL), Min-min Schedule Length (MmSL), Genetic Algorithm (GA), and Ant Colony Optimization (ACO). While the modifications of the MSL, MmSL and GA approaches from their original implementation are somewhat straight-forward, we design a novel structure using ACO. The performance comparisons of these four techniques are performed and the results are discussed. This paper not only gives a suggestion on which heuristic is best suited for the specific problem, but also provides a new direction to solve similar problems.

Endoscopic sinus surgery (ESS) is typically performed on an outpatient basis in our centre. The purpose of this study is to determine the frequency of unexpected stays in patients who undergo ESS. This information would be useful to identify and to counsel these potential patients.Retrospective chart review of 194 consecutive patients who had ESS during a 6-month span. Multivariate analysis was performed on 11 variables identified in the charts to determine whether any of the data predicted an unexpected admission.The unexpected rate of admission was 4.7%. Surgical complications causing admission occurred in 1% of the cases. Reasons for admissions included nausea and vomiting, hypotension, oxygen desaturation, headache, postoperative epistaxis, and observation for possible cerebrospinal fluid leak. None of the 11 variables that were examined showed statistical significance as independent predictors of unexpected admissions. However, two variables, the presence of comorbidities and the use of ondansetron, did approach statistical significance.Unexpected admissions following ESS are infrequent, and the reasons for admission are varied. In this study, although 9 of the 11 parameters evaluated showed no statistical significance as independent predictors of unexpected admissions, 2 did approach statistical significance. Intuitively, the presence of patient comorbidities would be expected to place the patient at greater risk of unexpected admission. Ondansetron is a potent antiemetic and is reserved for patients at risk or in those having severe symptoms. These patients would also be expected to have an increased risk of an unanticipated hospital stay.

This paper introduces the scheduling of frame-based real-time tasks in partitioning schemes for multiprocessor systems powered by rechargeable batteries. In frame-based real-time systems, a set of tasks must execute in a frame, and the whole frame is repeated. This system model is widely used in real-time communication, real-time imaging and a lot of other real-time/embedded systems. Nowadays, many of these systems are powered by rechargeable batteries. Scheduling real-time tasks on these rechargeable systems is an important yet largely ignored issue. The problem for uniprocessor systems had been studied in (A. Allavena and D. Mosse, 2001), in which an algorithm of complexity O(N) was proposed for determining the feasibility of the task set. However, it poses a challenge when doing so in a rechargeable multiprocessor system considering different characteristics of the batteries. In this paper, we first show this problem to be NP-hard, and then propose efficient algorithms to overcome it. The simulation results have shown that our algorithms exhibit very good behaviors and they can be considered as solutions to the problem.

The frontal recess can be a difficult area to manage postoperatively as recurrent disease and stenosis may obstruct drainage of the frontal sinus. Frontal sinus stents may be used to maintain patency temporarily. We reviewed the outcomes of frontal sinus stents left in patients for longer than 3 months to determine how long a long-term frontal stent can be left in situ.Retrospective chart review of patients who had frontal sinus stents in situ for 3 months or longer during a 6-year span.A retrospective review of patients who had frontal stents in situ longer than 3 months from April 2000 to March 2006. Eleven charts were reviewed.Eleven patients had 21 frontal stents placed. Ten stents were still in situ at the end of the period studied. In the remaining 11 stents, the average duration of placement was 16.3 months. The spontaneous dislodgement rate was 14%, occurring at an average of 8.8 months. Irreversible obstruction, complication, and failure rates were 5%, 5%, and 9%, respectively.In this series, long-term frontal stents (defined as those left in for longer than 3 months) have been safely left in situ for an average of 16.3 months. Benefits include relative ease of placement and good patient tolerance. Disadvantages include periodic stent replacement from dislodgement or obstruction, the occasional need for suctioning to maintain patency, and the potential for stent migration into the frontal sinus. One of 11 patients had a failure of symptom control, requiring additional frontal sinus surgery.

Optical burst switching (OBS) is a promising solution for allowing various-size data burst to be transported optically over dense wavelength division multiplexing (DWDM) without O/E/O (optical/electronic/optical) conversion. In OBS, networks, burst headers are sent ahead of the data bursts on a separate control channel to set up optical paths for the data bursts. While data bursts travel entirely in the optical domain, the burst headers have to be converted to electronic form and processed electronically. As the data channel bandwidth increases dramatically, the electronic control path for header processing is likely to become the performance bottleneck. It has been shown that control path overloading can severely degrade the performance of an OBS router. In this paper, we propose to formulate the burst header scheduling problem as an on-line time-constrained optimization problem for which we present a novel priority assignment method and a greedy on-line algorithm that consider both the urgency of the headers and the lengths of the bursts that the headers are representing. To the authors' best knowledge, it is the first paper that targets on solving control channel's overloading in OBS networks by improving the performance on throughput, as well as burst loss rate. Simulation results have shown that our technique is very effective.

Anthrapyrazoles have been investigated as cancer chemotherapeutic agents. The mechanism of action of these compounds is thought to involve inhibition of DNA topoisomerase II. A structure-activity study was carried out to determine the in vitro cytotoxic activity of nine novel anthrapyrazoles against human breast carcinoma, head and neck squamous cell carcinoma and leukemia cells, and against Chinese hamster ovary cells. The activity of these anthrapyrazole analogues was compared with that of two clinically tested anthrapyrazoles, losoxantrone and piroxantrone. Inhibition of topoisomerase II as a mechanism of action for the analogues was also investigated. The cytotoxic activity of the analogues was determined in vitro by MTT cell growth inhibition assay and inhibition of catalytic topoisomerase II activity by each compound was measured using a fluorometric DNA decatenation assay. All of the anthrapyrazole analogues inhibited the growth of the four cell lines with IC50 values that ranged from 0.1 to 45.2 microM. Losoxantrone was the most potent of the anthrapyrazole analogues studied. A tertiary amine in the basic side chain at N-2 increased the cytotoxic activity compared with a secondary amine in this side chain for many of the analogues, but not if there was a basic side chain at the C-5 position. A chlorine substituent on the basic side chain at N-2 did not have a consistent effect on activity. Moving the position of a chlorine substituent from C-5 to C-7 or introducing a basic side chain at C-5 did not have a consistent effect on cytotoxic activity. Anthrapyrazole analogues showed a broad range of activity for inhibiting topoisomerase II decatenation activity. Losoxantrone and piroxantrone were the most potent inhibitors of topoisomerase II activity. There was no significant correlation between the cytotoxic activity of the anthrapyrazole analogues and their ability to inhibit decatenation by topoisomerase II.

Anthrapyrazoles have been investigated as cancer chemotherapeutic agents. The mechanism of action of these compounds is thought to involve inhibition of DNA topoisomerase II. A structure-activity study was carried out to determine the in vitro cytotoxic activity of nine novel anthrapyrazoles against human breast carcinoma, head and neck squamous cell carcinoma and leukemia cells, and against Chinese hamster ovary cells. The activity of these anthrapyrazole analogues was compared with that of two clinically tested anthrapyrazoles, losoxantrone and piroxantrone. Inhibition of topoisomerase II as a mechanism of action for the analogues was also investigated. The cytotoxic activity of the analogues was determined in vitro by MTT cell growth inhibition assay and inhibition of catalytic topoisomerase II activity by each compound was measured using a fluorometric DNA decatenation assay. All of the anthrapyrazole analogues inhibited the growth of the four cell lines with IC50 values that ranged from 0.1 to 45.2 microM. Losoxantrone was the most potent of the anthrapyrazole analogues studied. A tertiary amine in the basic side chain at N-2 increased the cytotoxic activity compared with a secondary amine in this side chain for many of the analogues, but not if there was a basic side chain at the C-5 position. A chlorine substituent on the basic side chain at N-2 did not have a consistent effect on activity. Moving the position of a chlorine substituent from C-5 to C-7 or introducing a basic side chain at C-5 did not have a consistent effect on cytotoxic activity. Anthrapyrazole analogues showed a broad range of activity for inhibiting topoisomerase II decatenation activity. Losoxantrone and piroxantrone were the most potent inhibitors of topoisomerase II activity. There was no significant correlation between the cytotoxic activity of the anthrapyrazole analogues and their ability to inhibit decatenation by topoisomerase II.

To assess the hemodynamic and hemostatic effects of 2 different concentrations of epinephrine in local anesthetic used during functional endoscopic sinus surgery (FESS). Injection of local anesthetic containing epinephrine during endoscopic sinus surgery, while providing hemostasis, has been associated with cardiac adverse effects such as tachycardia, hypertension, as well as arrhythmias.Double-blind, randomized clinical trial.Tertiary referral center.A total of 140 patients undergoing FESS randomly divided into 2 groups, with group 1 receiving lidocaine hydrochloride, 2%, with 1:100 000 epinephrine and group 2, lidocaine, 2%, with 1:200 000 epinephrine.Baseline and postinjection hemodynamic parameters were recorded at 1-minute intervals for 5 minutes. Patient demographics, the extent of surgery, and the presence of polyps were recorded in both groups. Hemodynamic and hemostatic parameters and intraoperative blood loss were compared.Significant hemodynamic fluctuations were noted following injection of lidocaine, 2%, with 1:100 000 epinephrine (group 1). Increases in heart rate and systolic, diastolic, and mean arterial blood pressure were noted in group 1 patients. The increase was found to be significant (P.001) in the first and second minutes after injection and decreased to baseline level by the fifth minute. This fluctuation was not noted in group 2 patients, who received lidocaine, 2%, with 1:200 000 epinephrine. Using a standardized scale to assess surgical bleeding, no statistical difference in the 2 groups was observed (P.05).Submucosal injection of lidocaine, 2%, with 1:200 000 epinephrine during FESS does not lead to hemodynamic fluctuations or increased intraoperative bleeding compared with lidocaine, 2%, with 1:100 000 epinephrine.clinicaltrials.gov Identifier: NCT00852410.

One pot reaction of anilines, benzaldehydes and 2-pyrrolines under lanthanide triflate catalysis affords substituted hexahydropyrrolo[3,2-c]quinolines in good to excellent yields.