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991.
Software reuse could be implemented at several levels including the specification level, design level, program/subprogram library level, code level, and object-code level. However, reuse has a distinct definition for each of the above-mentioned levels. Moreover, the techniques applied to organize and manage reuse is different from one level to another. What's more, the complexity of the reuse methods and techniques increases as it moves from the specification level to the code and object-code levels. On the positive side, the time and space efficiency resulting from the application of reuse techniques improves in the same direction. Specification and design levels are at higher levels of abstraction than the other reuse levels, therefore their potential for accommodating reuse is greater and their adaptation to new applications can be simpler. However, the reuse process of the specification and design levels ultimately involves coding (be it system-generated or manual), testing, and debugging. On the other hand, reuse at code and object-code levels essentially eliminates coding and overall testing, hence it is more economical where a large collection of reusable software is organized in a software library  相似文献   
992.
Computer-aided engineering tools are routinely used to simulate forging and heat-treatment operations and to perform thermal and stress analyses. This review gives a few examples of the current uses of process modeling tools and outlines some developing capabilities and near-term applications.  相似文献   
993.
994.
Translated from Fiziko-Khimicheskaya Mekhanika Materialov, No. 5, pp. 51–56, September–October, 1992.  相似文献   
995.
We investigated the effect of bioflavonoid quercetin on tyrosine phosphorylation and phospholipase D (PLD, EC 3.1.4.4) activation in rabbit peritoneal neutrophils stimulated by N-formylmethionyl-leucyl-phenylalanine (fMLP). The quercetin dose-dependently inhibited degranulation and superoxide production in fMLP-stimulated neutrophils. A strong inhibitory effect of quercetin on the tyrosine phosphorylation of several proteins (40, 42, 43, 45, 46 and 75 kDa) was observed when the neutrophils were pretreated with different concentrations of quercetin. Furthermore, quercetin inhibited mitogen activated protein kinase (MAP kinase) and PLD activation induced by fMLP in a dose-dependent manner. The reduction in PLD activity was 30% at 0.1 microM and 70% at 100 microM of quercetin. These results suggest that impairment of neutrophil functions by quercetin may be due, at least in part, to inhibition of tyrosine phosphorylation and PLD activation.  相似文献   
996.
997.
The authors study the performance of a multichannel modulation method for asymmetric digital subscriber lines (ADSLs) and very high-speed digital subscriber lines (VHDSLs). In the ADSL case, over all unloaded North American subscriber lines in the test set, a unidirectional 1.536 Mb/s data rate service from the end office to the customer premises is possible on a single twisted pair at an error rate of 10-7 with at least a 6 dB margin used coded multichannel modulation with sufficient transmit power. In the VHDSL case, data rates in excess of 100 Mb/s can be transmitted reliably, at an error rate of 10-7, using uncoded multichannel modulation on a single twisted pair over a distance ⩽150 ft with a sufficiently high sampling rate (≈24 MHz) and transmit power. It is shown that a cost-effective multichannel transceiver design suggested for high-speed digital subscriber line (HDSL) service will also work well for ADSL and VHDSL services with only minimal modifications  相似文献   
998.
The time-of-flight method is studied using coincident annihilation gamma rays with an energy of 511 keV to find the distance from a surface at which they are scattered back for detection. The gamma rays have a good penetration ability, which makes the method suitable for industrial circumstances in which the range is rendered opaque to light by flue gas and aerosols. An accuracy of 1 cm over a distance of 2 m can be obtained by increasing the averaging time by the square of the lengthening factor. The density of the surface can be studied by recording the width of the distribution of the surface measurements. This measurement needs a prolonged averaging time, but the thickness of the slag layer on top of a steel melt can be measured with a maximum error of 1.5 cm at short distances, for example  相似文献   
999.
Virtual Models of the Synthesis of Nanosystems   总被引:1,自引:1,他引:0  
The problem of synthesis of nanosystems reproducible on the microscopic level is analyzed in the framework of the adiabatic approximation. Different methods for describing the structure of polyatomic systems are discussed. Special attention is focused on algorithmic information. The operation of a configurational machine that makes it possible to simulate actually proceeding chemical processes, in particular, synthesis of nanosystems, is considered in detail.  相似文献   
1000.
The broad acceptance of mobile technology has undoubtedly created new opportunities in communication. The proposed environment attempts to enhance the information flow among the members of a department and, furthermore, to provide a test-bed mobile Web application for students undertaking Internet technologies courses. The key ideas are to support the educational process to provide auxiliary access to educational information sources, such as announcements, course schedules, grades, and user directory details. As a second system integration step, additional mobile Web services were introduced, such as application forms of the department's administration office, project assignment, and discussion groups. Technological evaluation and students' feedback indicate that the proposed solution is both efficient in communication perspective and effective for student involvement in the mobile Web initiative. Future steps include multimedia messages (MMS) integration and third-generation (3G)-based information delivery.  相似文献   
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