基于Web的信息技术考试系统的设计与实现过程

基于Web的考试系统是考试的发展方向，是远程教育的一个重要组成部分．它采用B／S模型．本文分析了基于WEB系统的考试模型及功能，研究了考试系统实现的关键技术，并在具体系统中做了实现．     

Judicious Use of Multiple Hypothesis Tests

Abstract:  When analyzing a table of statistical results, one must first decide whether adjustment of significance levels is appropriate. If the main goal is hypothesis generation or initial screening for potential conservation problems, then it may be appropriate to use the standard comparisonwise significance level to avoid Type II errors (not detecting real differences or trends). If the main goal is rigorous testing of a hypothesis, however, then an adjustment for multiple tests is needed. To control the familywise Type I error rate (the probability of rejecting at least one true null hypothesis), sequential modifications of the standard Bonferroni method, such as Holm's method, will provide more statistical power than the standard Bonferroni method. Additional power may be achieved through procedures that control the false discovery rate (FDR) (the expected proportion of false positives among tests found to be significant). Holm's sequential Bonferroni method and two FDR-controlling procedures were applied to the results of multiple-regression analyses of the relationship between habitat variables and the abundance of 25 species of forest birds in Japan, and the FDR-controlling procedures provided considerably greater statistical power.     

Small female rib cage fracture in frontal sled tests

Objectives: The 2 objectives of this study are to (1) examine the rib and sternal fractures sustained by small stature elderly females in simulated frontal crashes and (2) determine how the findings are characterized by prior knowledge and field data.

Methods: A test series was conducted to evaluate the response of 5 elderly (average age 76 years) female postmortem human subjects (PMHS), similar in mass and size to a 5th percentile female, in 30 km/h frontal sled tests. The subjects were restrained on a rigid planar seat by bilateral rigid knee bolsters, pelvic blocks, and a custom force-limited 3-point shoulder and lap belt. Posttest subject injury assessment included identifying rib cage fractures by means of a radiologist read of a posttest computed tomography (CT) and an autopsy. The data from a motion capture camera system were processed to provide chest deflection, defined as the movement of the sternum relative to the spine at the level of T8.

?A complementary field data investigation involved querying the NASS-CDS database over the years 1997–2012. The targeted cases involved belted front seat small female passenger vehicle occupants over 40 years old who were injured in 25 to 35 km/h delta-V frontal crashes (11 to 1 o'clock).

Results: Peak upper shoulder belt tension averaged 1,970 N (SD = 140 N) in the sled tests. For all subjects, the peak x-axis deflection was recorded at the sternum with an average of ?44.5 mm or 25% of chest depth. The thoracic injury severity based on the number and distribution of rib fractures yielded 4 subjects coded as Abbreviated Injury Scale (AIS) 3 (serious) and one as AIS 5 (critical). The NASS-CDS field data investigation of small females identified 205 occupants who met the search criteria. Rib fractures were reported for 2.7% of the female occupants.

Conclusions: The small elderly test subjects sustained a higher number of rib cage fractures than expected in what was intended to be a minimally injurious frontal crash test condition. Neither field studies nor prior laboratory frontal sled tests conducted with 50th percentile male PMHS predicted the injury severity observed. Although this was a limited study, the results justify further exploration of the risk of rib cage injury for small elderly female occupants.     

浅谈社会转型期加强和改进政治权力制约问题

本文从社会转型期容易产生腐败问题为切入点,分析了加强和改进政治权力制约的必要性,并根据我国的实际情况,提出了为治理和减少腐败而加强和改进对政治权力制约的对策和办法。     

Effects of LATCH versus Available Seatbelt Installation of Rear Facing Child Restraint Systems on Head Injury Criteria for 6 Month Old Infants in Rear End Collisions

Objective: The Lower Anchor and Tethers for CHildren (LATCH) system was introduced in vehicles made after September 1, 2002 and intended to make installation of rear and forward-facing child safety seats easier. Due to the lack of rear impact testing of RFCRS required per the Federal Motor Vehicle Safety Standards (FMVSS), the purpose of this study was to explore the effects, if any, of installation method of RFCRS on the performance of commonly purchased makes and models of RFCRS. Specifically, we hypothesize that in a 48 km/h (29.8 MPH) rear-end collision, installation of RFCRS using the LATCH system will result in higher Head Injury Criteria (HIC) values when compared to using the available lap/shoulder seatbelt (Emergency Locking Retractor - ELR or Automatic Locking Retractor - ALR).

Methods: The test matrix included 36 rear impact sled tests conducted using 3 installation methods on 3 models of RFCRS: the Graco SnugRide® with and without the base, the Britax Chaperone with base-mounted anti-rebound bar, and the Evenflo Tribute®, a model of convertible rearward/forward facing restraint system used in the rearward facing mode. The seats were installed using the LATCH system, ELR lap/shoulder belts, or ALR lap/shoulder belts in seating positions 4 and 6 on a vehicle buck mounted to the sled test base. The infant seat and 6 month old CRABI anthropometric test device (ATD) installation methods were in accordance with standards set forth in the National Highway Traffic Safety Administration's (NHTSA) FMVSS No. 213, Child Restraint Systems. All tests were conducted on pneumatic controlled acceleration sled (HYGE, Inc., PA, USA) at 48 km/h.

Results: Installation of infant seat type RFCRS using the LATCH system resulted in higher HIC₁₅ values when compared to using the available lap/shoulder seatbelt (ELR or ALR). The mean HIC₁₅ values were most severe when infant seat type RFCRS were installed using LATCH (Graco SnugRide® HIC₁₅ = 394 and Britax Chaperone HIC₁₅ = 133) compared to using either ELR lap/shoulder belts (Graco SnugRide® HIC₁₅ = 218 and Britax Chaperone HIC₁₅ = 65) or ALR lap/shoulder belts (Graco SnugRide® HIC₁₅ = 194 and Britax Chaperone HIC₁₅ = 78). The installation method did not result in a statistically significant difference in HIC for the convertible type RFCRS (Evenflo Tribute®). In many of the tests, the ATD's head struck the seatback in which the RFCRS was installed. These head strikes resulted in the higher HIC₁₅ scores recorded throughout the testing.

Conclusions: The results of this study suggest that LATCH does not offer equal protection to lap/shoulder belts from head injuries in rear impacts when used with infant seat type RFCRS.     

道路车辆电工电子设备高加速应力筛选和稽核

成熟的汽车企业已经将高加速环境应力筛选和稽核引入装车电工电子设备的研发、试产和批量供货的管理中,其需求已进入国内检测市场。在讨论了高加速寿命试验(HALT)基础上,介绍并讨论高加速应力筛选(HASS)和稽核(HASA)的各项要素和实验室要求。     

空气中二氧化硫检测的能力验证

为了解对空气中二氧化硫的检测能力,由广西壮族自治区环境监测中心站具体实施了空气中二氧化硫检测能力验证工作。广西的59个实验室参加了本次能力验证。检测结果统计和评价方法为四分位稳健统计。结果显示：获得满意结果的实验室44家,满意结果率为74.6％,可疑结果的有6家,可疑率为10.2％,不满意结果的有9家,不满意率为15.2％。参加能力验证的绝大多数实验室可以准确检测空气中的二氧化硫。     

英国消油剂批准和认可制度及对中国的启示研究

喷洒消油剂作为溢油应急的一种方法,简单、快速且能在大多数的海况下使用,在溢油应急中发挥了不可替代的作用。但由于消油剂是一种化学物质,对环境具有二次污染危险,所以消油剂的使用广受质疑。英国将消油剂作为主要的溢油应对措施,经过30年不断改进已形成了完善的包括消油剂在内的溢油处理产品批准和使用许可制度。通过对英国消油剂制度总结和分析,梳理并提出对中国政府主管部门改进、完善消油剂管理制度的建议。     

我国基本农田保护制度的政策评价与完善研究

我国基本农田保护制度的变迁是典型的供给主导型制度变迁。本文从我国基本农田保护制度的概念与内涵谈起,分阶段分析了我国基本农田保护制度的形成与发展的演变过程,重点对改革开放后的基本农田保护制度绩效进行了评价与分析。并对我国现阶段基本农田保护失控的原因进行了制度层面上的分析,最后给出相关政策建议。