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Response to the outbreak of COVID-19, classes in this semester are mainly replaced by online teaching to ensure continual learning. Teachers are actively exploring effective online teaching methods to provide a good learning experience for students at home. This paper presents an online teaching model based on the idea of Problem-Based Learning (PBL) and take “Data Structure” as an example to discuss the design of teaching process and problems.

Parallel computing model plays a great basic role in advanced computing; Based on researching existing parallel computing models, this paper brings forward a parallel computing model-Layer Forward Net toward Cubic-R architecture, and describes the model's structure, parameter, logic abstractly. Lastly towards typical N-Body problem, this paper designs a parallel algorithm, and analyses its complexity. The compared result shows that this model has low computing complexity, increase by layer and other merit.

In order to analyze the trajectories of homing depth charge attacking the submarine, the paper establishes the mathematical model of longitudinal trajectory for homing depth charge with different control orderlinesses and uses MATLAB/Simulink to carry on simulation research for the trajectory when the target was moving with invariable speed in a beeline. The result indicates that the trajectories of homing depth charge are affected by different control orderlinesses when attack the same submarine.

The main objective of this paper is to supply scientific basics for preventing and forecasting the prevalence of hand, foot and mouth disease to explore the effect of different meteorological conditions on occurrence of hand, foot and mouth disease in Wuwei City, northwestern China. Here the data about the diseases and weather was collected from 2008–2010, and the correlation analysis, multiple linear regression and exponential curve fitting methods were made. The results showed that 2688 cases of hand, foot and mouth disease were collected from 2008 to 2010, and the annual average incidence was 47.62/100,000. The average prevalence of hand, foot and mouth disease at Liangzhou District, Minqin County, Gulang County and Tianzhu Tibetan Autonomous County were 42.69, 38.52, 65.92 and 49.18 per 100,000 respectively. This disease occurred year-round in Wuwei City, but had a clear seasonal climax. Generally, the incidence increased from April and rose to the first peak in May, Jun, July respectively. The second peak was in September or October every year. Different meteorological factors had different impact on the epidemic of disease in four areas, such as average temperature, relative humidity, atmospheric pressure, rainfall and evaporation capacity. The results of multiple linear regressions indicated that relative humidity and atmospheric pressure were the main influence factors in Liangzhou District, average temperature in Gulang County, atmospheric pressure in Tianzhu County. The incidence of the disease and average sunshine hours showed exponential function relationship in Minqin County. In conclusion, different weather conditions have different impact on the prevalence of hand, foot and mouth disease. A high correlation exists in four areas of Wuwei City between meteorological factors and hand, foot and mouth disease occurrence. And summer and autumn were the important seasons to prevent and control the disease.

Based on the meteorology data of the main capital cities in China from 1951 to 2008, average temperature and wind effect index (K) were calculated and by means of linear regression, Spearmen's rank correlation and change rate, the tendency of temperature and wind effect index were analyzed by year, season and spatial. The results showed that in recent 58 years, the average annual temperature of the main capital cities showed an obvious upward trend with the speed of 0.3 centigrade per ten years. And the rising tendency in north of China was most obvious with the speed of 0.47 centigrade per ten years. In addition, the average of annual wind effect index (K) also revealed the same tendency with the speed of 10.8 per ten years. And with the speed of 20.6 per ten years, wind effect index increased most rapidly in northeast of China. During different season wind effect index (K) showed varying range of variation, which meant the range of change was biggest in winter while smallest in summer. The spatial distribution revealed that wind effect index (K) was higher in South of China, while lower in North of China all the year round.

NC turret of CNC machine tool is a kind of typical complex subsystem with complicated structure and failure styles. The failure of NC turret is so complicated that the failure data obtained from reliability analysis includes abnormal data, which could bring some error to analysis result. This paper presented a method to eliminate abnormal. Especially, the probability model is discussed in detail. The failure data of some certain CNC machine tool turret is applied to valid the method of eliminating abnormal data presented above. Then, analyze the reliability of NC turret with the remaining data, and obtain its MTBF.

The logarithmic spiral curved arch dam (LSCAD) is a new type of dam. Based on mathematic equations developed for the arch rings of the LSCAD and automatic mesh generation techniques, a mesh generation system for the LSCAD was constructed. Differnt design patterns, including strategy pattern, facade pattern, CAD-mesh separation pattern and embedded element pattern, were employed in this system. It is demonstrated that, by using these patterns, the reliability, reusability, maintainability and scalability of the system can be greatly improved. At last, specific examples of mesh generation using the developed system are presented graphically.

Nowadays, Product structure data becomes the important exchanging data among collaborative enterprise, which establishes the relationships between parts of product. The paper brings forward a method of building Virtual PDM to solve the Product Structure Date exchange problem in heterogeneous PDM systems of each enterprise. Firstly, data model of product structure data is described. The framework of VPDM-Based Product Structure Date exchange is proposed and the parts that compose the whole are analyzed. And then, the technology framework based on J2EE is founded. At last, the paper lists the system configuration implementing the framework and the data exchange sequence. Using this method, Product structure data among three heterogeneous PDM softwares has been successful exchanged.

Radio Frequency Identification (RFID) anti-collision algorithm is an important technique in RFID field. In this paper, we first mathematically investigate the relationship among the number of tags, the number of slots and the probability of success to read a tag, and then present a precise and reasonable method to evaluate the efficiency of a RFID anti-collision system. In the proposed method, we introduce slot time parameter into the anti-collision process. After introducing the parameter and making it optimal, we find the number of tags no longer equals the number of the frame slots, but fluctuates with the slot time. After the simulation, results show a much better performance.

A new coagulant of calcic and aluminum HCA was used to decolorize the CTMP wastewater. The results showed that in the condition of pH 4 to pH 7 and the dosage of HCA 4ml to 7ml per 100ml wastewater, the color of CTMP effluent could be decreased from 25600C.U. to below 80C.U. with the increase of biodegradation of wastewater. The mechanisms of decolorization were analyzed by UV/VIS spectrometer, FT-IR instrument and GC-MS spectrometer, the results showed that it was the flocculation with lignin structure could the coagulant of calcic and aluminum got good effects of decolorization.

Computer networks provide an increasing number of services that require complex processing of packets, for example firewalls, load balancing, network storage, and TCP/IP offloading. Such services require the use of powerful network processors to provide the necessary performance and flexibility. But NPs also introduce new challenges. It is important to study the performance of NP system so that one can take full advantage of NP resources to achieve the required performance for a given application. It is therefore desirable to develop a framework for analyzing performance of NP-based applications. The framework divides the network processor system into four levels, and incorporates Petri net, AD AG and a new analysis method- "line space" to evaluate NP-based system performance, which simplifies the complexity of multilevel parallel system performance evaluation and insures its efficiency and precision. We apply our methodology to an Intel's reference design, and show that the analytical results using our method match the experimental results from actual implementation.

In this work, we present a new methodology to calculate the available compute budget which determines how much processing the network processor can perform on each packet with different length. To evaluate the method, we also did a wide range of tests with different length packets. Then we analysis the MicroEngine states with the test results, which is useful in building the applications on network processors and evaluating its performance. We also give several solutions to solving the applications' performance bounds such as latency bound and compute bound, which are caused by variable length packets.

Aiming at the limitations of benchmark tools, the paper brings a model, which is beneficial for NP-based application design, and which ought to be obeyed on the four levels of system, function, task and hardware. Then five formulas are given specifically for Intel NPbased application design. In the third part, an study case and it’s testing result are given with these disciplines and formulas applied. Finally the paper points out under which circumstances can these formulas be applied.