ASLR and other defense measures have been deployed in modern computers against memory data leakage and control flow hijacking, which are two common vulnerability exploitation methods, but attackers ...can always bypass these security defense mechanisms to attack the computer. For the problem of the randomization strategy in ASLR technology is partial-oriented memory space. This paper presents a heap randomization strategy for the entire heap memory space. By changing the access order of memory pool, the strategy reduces the time consumption of memory region search, a random memory block allocation algorithm is proposed to increase the unpredictability of heap memory addresses and improve the security of computer systems. The randomization algorithm increases the variation interval of memory block gap by adding randomization parameters, then through the attack experiment and time performance experiment, the appropriate randomization parameters are determined to ensure the efficiency of the algorithm.
In contrast to earlier studies, we find that inventory holding in the US has become much more efficient since the mid-1980s. This result is found by examining trends in fixed weight aggregate ...inventory to sales ratios rather than traditional inventory to sales ratios, whose trends are shown to have been distorted by shifts in the composition of sales towards sectors carrying heavier stocks. Nearly all of the reductions in inventory holdings relative to sales are found to have occurred in sectors carrying durable goods. The adoption of just-in-time (JIT) and other inventory control systems by Durable Manufacturers is shown to have greatly reduced their inventory holdings.
Pycket: a tracing JIT for a functional language Bauman, Spenser; Bolz, Carl Friedrich; Hirschfeld, Robert ...
Proceedings of the 20th ACM SIGPLAN International Conference on Functional Programming,
08/2015
Conference Proceeding
Odprti dostop
We present Pycket, a high-performance tracing JIT compiler for Racket. Pycket supports a wide variety of the sophisticated features in Racket such as contracts, continuations, classes, structures, ...dynamic binding, and more. On average, over a standard suite of benchmarks, Pycket outperforms existing compilers, both Racket's JIT and other highly-optimizing Scheme compilers. Further, Pycket provides much better performance for Racket proxies than existing systems, dramatically reducing the overhead of contracts and gradual typing. We validate this claim with performance evaluation on multiple existing benchmark suites. The Pycket implementation is of independent interest as an application of the RPython meta-tracing framework (originally created for PyPy), which automatically generates tracing JIT compilers from interpreters. Prior work on meta-tracing focuses on bytecode interpreters, whereas Pycket is a high-level interpreter based on the CEK abstract machine and operates directly on abstract syntax trees. Pycket supports proper tail calls and first-class continuations. In the setting of a functional language, where recursion and higher-order functions are more prevalent than explicit loops, the most significant performance challenge for a tracing JIT is identifying which control flows constitute a loop---we discuss two strategies for identifying loops and measure their impact.
Lean approach: some insights Mohan, Ashutosh; Sharma, Sunil
Journal of advances in management research,
10/2003, Letnik:
1, Številka:
1
Journal Article
Recenzirano
Organizations are realizing the fact that it takes more than quality, cost, and delivery commitments to ensure survival. Organizations are recognizing the need for extra efforts in terms of ability ...to adjust quickly and effectively to demand fluctuations as well as product diversification according to the requirement of customer. The remedy, to face and come out as winner from this critical scenario, is the adoption of lean approach. The paper tries to trace the evolution of lean approach with an effort to re-define the efficiency and effectiveness parameters under lean thinking. The paper also deals with the underlying principles of lean approach. The main objective of this paper lies in our proposed model, which shows the scope of SCM under lean operations. Finally, the paper exposes the benefits of lean approach at different levels of organization and customers.
JIT instrumentation Olszewski, Marek; Mierle, Keir; Czajkowski, Adam ...
Proceedings of the 2nd ACM SIGOPS/EuroSys European Conference on Computer Systems 2007,
03/2007
Conference Proceeding
As modern operating systems become more complex, understanding their inner workings is increasingly difficult. Dynamic kernel instrumentation is a well established method of obtaining insight into ...the workings of an OS, with applications including debugging, profiling and monitoring, and security auditing. To date, all dynamic instrumentation systems for operating systems follow the probe-based instrumentation paradigm. While efficient on fixed-length instruction set architectures, probes are extremely expensive on variable-length ISAs such as the popular Intel x86 and AMD x86-64. We propose using just-in-time (JIT) instrumentation to overcome this problem. While common in user space, JIT instrumentation has not until now been attempted in kernel space. In this work, we show the feasibility and desirability of kernel-based JIT instrumentation for operating systems with our novel prototype, implemented as a Linux kernel module. The prototype is fully SMP capable. We evaluate our prototype against the popular Kprobes Linux instrumentation tool. Our prototype outperforms Kprobes, at both micro and macro levels, by orders of magnitude when applying medium- and fine-grained instrumentation.
Byte addressable, Non-Volatile Memory (NVM) is emerging as a revolutionary technology that provides near-DRAM performance and scalable memory capacity. To facilitate the usability of NVM, new ...programming frameworks have been proposed to automatically or semi-automatically maintain crash-consistent data structures, relieving much of the burden of developing persistent applications from programmers.
While these new frameworks greatly improve programmer productivity, they also require many runtime checks for correct execution on persistent objects, which significantly affect the application performance. With a characterization study of various workloads, we find that the overhead of these persistence checks in these programmer-friendly NVM frameworks can be substantial and reach up to 214%. Furthermore, we find that programs nearly always access exclusively either a persistent or a non-persistent object at a given site, making the behavior of these checks highly predictable.
In this paper, we propose QuickCheck, a technique that biases persistence checks based on their expected behavior, and exploits speculative optimizations to further reduce the overheads of these persistence checks. We evaluate QuickCheck with a variety of data intensive applications such as a key-value store. Our experiments show that QuickCheck improves the performance of a persistent Java framework on average by 48.2% for applications that do not require data persistence, and by 8.0% for a persistent memcached implementation running YCSB.
In this work, we propose an approach for transparent compilation and execution of Java programs onto Intel FPGA devices. In detail, we showcase how a managed runtime environment can leverage Intel ...OpenCL SDK to generate specialized FPGA code, enabling prototyping and acceleration of Java Programs onto FPGAs. Finally, we describe our implementation in the context of TornadoVM with a clear objective to ease FPGA programmability allowing integration with existing frameworks.
This paper looks at the successes and disappointments of MRP. It studies numerous articles to determine what the key shortcomings of MRP are. Next, it investigates if these failures are correctable, ...and what the consequences of not correcting these deficiencies means. This article considers alternatives that have been discussed in the current literature. Last of all this article discusses whether the improvements these alternatives suggest are sufficient to make MRP worth salvaging, or whether MRP is a system that needs to be discarded in favor of systems such as JIT (Just-in-Time), Optimized Production Technology (OPT), Theory of Constraints (TOC), and Bottleneck Allocation Methodology (BAM).
Just in time is an advanced manufacturing philosophy, which is practiced all over the world by organizations to achieve excellence in their performance. As most of the Original Equipment ...Manufacturers (OEM) are managing their supplies on JIT basis, their vendors are under tremendous pressure to adopt JIT. The JIT principles seems easy to adopt, yet many organizations fail to implement it. The implementation of JIT requires a radical change in the way of working at all level of the organization starting from top management to maintaining good customer relations. Indian Corrugated Packaging Industries play a very important role especially at the final dispatch of the product. This research paper tries to find out the readiness of ICPI for the implementation of JIT. Also it tries to find out whether the type of company matters in the implementation of JIT. The survey was conducted in companies in National Capital Region (NCR) of India, mainly Delhi, Noida, Ghaziabad, Gurgaon and Faridabad. The implementation readiness of these companies based on company type was analyzed using analysis of variance (ANOVA). The result shows that there was a distinction between industries type (family owned, Private Limited and Limited) and level of JIT implementation. Further the Friedman test was used to find out the predominant principle in each type of the industries. The purpose of this study is to provide a roadmap to Indian Corrugated Packaging Industries to implement JIT successfully. The contribution of this paper is the identification of the implementation JIT issues for ICPI as well as the status of these companies based on their classification. The results of this study is matching with studies in other type of components, proving the universal nature of JIT principles.
In a previous International Journal of Production Economics article, a comparative model was presented for inventory costs of purchasing under economic order quantity (EOQ) with quantity discounts ...and a just-in-time (JIT) order purchasing system. This paper expands the comparative model to include a relevant cost component not considered in the previous article. The results of the revised model show differences in the conclusions reached in the previous article, more specifically, the superiority of JIT in virtually any type of inventory ordering purchase decision.
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