计算机病毒与防范

通过介绍计算机病毒的概念、分类、基本原理、产生的种种原因和传播途径等，总结了些常用的预防措施。     

基于遗传神经网络的入侵防御系统研究

网络安全在今天社会中变得越来越重要。入侵防御系统是信息安全性保证的重要组成部分之一，使用新的方法提高其实时性和适应性已经成为热点。对入侵防御系统基本原理进行研究的基础上，讨论了遗传算法和神经网络相结合在入侵防御中的应用，给出了采用代理技术的系统结构。     

蠕虫病毒的传播原理与防治

蠕虫病毒发展迅速,现在的蠕虫病毒融入了黑客、木马等功能,还能阻止安全软件的运行,危害越来越大。本文介绍了蠕虫病毒的定义,特点,结构及其在传播过程中的功能,最后介绍了蠕虫病毒的预防与治理。     

基于移动目标防御的内网防渗透技术研究

内网安全是当前计算机网络安全中的一个重要研究领域。本文提出了一种基于移动目标防御（Moving Target Defense）思想的内网防渗透技术,在通信过程中将主机的真实地址修改为动态变化的虚拟地址,使得攻击者的扫描探测失效,从而难以获取内网主机地址并开展网络渗透,提升内网的安全性。正常用户可通过主机域名查询虚拟地址,开展正常通信。该技术最后实现为网络接入设备形态,已在内网环境中测试。     

耐辐射球菌PprI蛋白对急性放射损伤小鼠防护作用的初步研究

研究耐辐射球菌PprI蛋白对哺乳动物急性放射损伤的防护作用,初步探讨其作为一种新的抗辐射蛋白的作用机制。将PprI蛋白或生理盐水注射入小鼠肌肉内,观察辐照后第1、7、14、28天小鼠外周血象以及小鼠骨髓、胸腺和脾脏淋巴细胞的凋亡情况。研究结果表明：与生理盐水注射组相比,PprI蛋白注射组外周血白细胞计数于照后第28天显著增高（p〈0．05）;外周血小板数和淋巴细胞百分率于照后第1、7天显著增高（p〈O．05）;PprI蛋白注射组脾脏淋巴细胞凋亡率在照后第1、7、14天明显降低（p〈0．05）;胸腺淋巴细胞凋亡率于照后第14和28天明显降低（p〈0．05）;骨髓细胞凋亡率在照后第1、14和28天明显降低（p〈0．05）;并且骨髓细胞凋亡率于照后第28天基本恢复正常。上述结果初步表明,耐辐射球菌PprI蛋白对哺乳动物急性放射损伤有着明显的防护作用。     

Automobile-Speed Estimation Using Movie-film Simulation

A silent movie film made by shooting through the windscreen of a car driven at different constant speeds was shown in an auditorium, and subjects asked to estimate the speed of the car. Of the 70 subjects who participated, 35 sat at the front and the remainder at the back.

The speed estimates of those seated at the back were, on average, some 11 per cent higher than those at the front. An explanation for this effect is given. It is shown that those at the correct perspective distance from the screen ( in the present case, those at the front) will receive an impression of speed which most closely resembles the actual speed of the car.

The speed estimates from the front of the auditorium most closely resembled those observed in an earlier field experiment when the subjects' hearing was diminished. It is concluded that the movie technique provides a good simulation of the task in the field experiment if the following two qualifications are made. First, the movie must be viewed from close to the correct perspective distance. Second, a silent movie corresponds to the real situation in which the observer is prevented from hearing.     

Optimal Duration of Endurance Performance on the Cycle Ergometer in Relation to Maximal Oxygen Intake

The problem was to determine the optimal duration of endurance performance on the bicycle ergometer using max [Vdot]o₂ as the criterion of validity. Max [Vdot]o₂ was measured in 50 male college students using the, step-increment method (the initial resistance was 2·5 at 60 rpm on a bicycle ergometer, and was increased by 0·5 kg each two minutes until the subject would no longer turn.the ergometer, or when the rate fell to 40 to 50 rev/min).,In contrast, the endurance performance test was of the ‘ steady- pace ’ type in which all of the subjects began pedalling at the same initial rate of 69. pedal rpm at a work rate of 1656 kgm/min for 12 minutes. Although the rate of pedalling (and thus the Work rate) declined as fatigue developed, the friction load remained constant at124 kg throughout the test. There were 12 endurance scores for each individual, endurance being measured as the cumulated work done up to a particular minute. The 12 scores ranged from no decrement in the case of a few subjects with complete endurance to 24 percent in the subjeots with least endurance.

The validity correlations (i.e., the min-by-min correlations between, max [Vdot]o₂and the 12 endurance scores), progressively increased to Y = 0·78 at minute 12. An empirical equation of the form, Y =C ? at, was used to fit. a smooth curve to the trend of the correlations so its' changing rate of curvature could be determined quantitatively. The rate of change was found to slow down considerably in the; later stages of performance, especially after minutes 7 or 8, where the change, was less than 0·04 correlation units.

It was concluded that max [Vdot]o₂ does hot predict endurance performance effectively unless the performance is continued for a least 8 minutes under the conditions of the present experiment. With a,12 minute test, the validity is 96 percent of the asymptotic value, suggesting little further gains can be expected beyond 12 minutes.     

Margin of safety for the human back: a probable consensus based on published studies

Despite numerous efforts to control occurrences of work-related low back pain, it continues to be a significant problem. Since the causation of low back pain is under multifactorial control, it is suggested that the factor most vulnerable at any given time will determine the safety. Epidemiological, biomechanical, physiological, and psychophysical information presented in published literature has been analysed. The data available are related to injuries and the projected margin of safety. This paper therefore, is an integrative, inferential synthesis of the published work to discern the margin of safety. An attempt has been made to conclude, on the basis of objective evidence, an all encompassing criterion to ensure the safety of the back. The psychophysical approach appears to integrate biomechanical and physiological variables on a short term basis in the studies surveyed. However, it remains to be proven that the sensory conditioning due to prolonged and repetitive occupational tasks will remain responsive to cumulative load and fatigue failures.     

计算机虚拟现实技术在消防数字预案中的应用

在我国现行的消防数字预案系统中,由于缺乏必要的技术改进,消防安全重点单位消防预案大多是纯文字和图表的,消防官兵通过阅读预案只能得到一个模糊的概念,无法更精确的分析,因而逐渐暴露出一些难以解决的问题.在这种情况下,计算机技术的发展,特别是近年来计算机虚拟现实技术的研究与开发,为消防数字预案系统的更新发展提供了一个良好的契机.     

浅议计算机信息安全所面临的威胁以及防范技术

伴随计算机互联网技术的普及和发展,人们在网络中得到便利的同时,也因为网络的自由和开放给我们的信息安全代理一定的威胁。本文针对网络信息安全的几个方面出发,结合现在网络信息安全的实际状况以及将来的发展趋势,有针对性的提出了信息安全所面临的威胁以及针对此威胁的一些防范措施。