Design and Implementation of Multi-collaborative Training System

With the rapid development of computer technology,network and information technology have been widely used in people’s daily lives,which has brought great convenience to labor and life.At the same time,people are increasingly dependent on computer technology.In this case,the social demand for computer professionals is increasing.However,due to the rapid changes and continuous updates of computer technology,the training of talents in computer specialty in China is far from meeting the demand and quality requirements of the society for this kind of talents.Colleges and universities are the important departments that cultivate computer professionals and technicians for the society.When cultivating talents in computer specialty,colleges and universities must conform to the requirements of the development of the times,adjust teaching strategies in a timely manner according to the actual needs of the society,build a talent training system,build a practical training teaching system of computer specialty,innovate teaching modes and teaching contents,and improve students’professional skills through perfect practical teaching,so as to ensure that they can skillfully apply computer technology to solve practical problems in the learning process and further improve their employment competitiveness.Therefore,this paper analyzes the practical teaching system of computer specialty,puts forward corresponding solutions to the existing problems,constructs a multi-collaborative practical training system,and implements the system.The implementation results show that the system can better meet the needs of students at different levels,and the results are fairer.Students’recognition and sense of acquisition of courses have also been greatly improved.The accumulated experience and data also provide good support for our continuous improvement of the system in the future.

Toward Coordination Control of Multiple Fish-Like Robots:Real-Time Vision-Based Pose Estimation and Tracking via Deep Neural Networks

Controlling multiple multi-joint fish-like robots has long captivated the attention of engineers and biologists,for which a fundamental but challenging topic is to robustly track the postures of the individuals in real time.This requires detecting multiple robots,estimating multi-joint postures,and tracking identities,as well as processing fast in real time.To the best of our knowledge,this challenge has not been tackled in the previous studies.In this paper,to precisely track the planar postures of multiple swimming multi-joint fish-like robots in real time,we propose a novel deep neural network-based method,named TAB-IOL.Its TAB part fuses the top-down and bottom-up approaches for vision-based pose estimation,while the IOL part with long short-term memory considers the motion constraints among joints for precise pose tracking.The satisfying performance of our TAB-IOL is verified by testing on a group of freely swimming fish-like robots in various scenarios with strong disturbances and by a deed comparison of accuracy,speed,and robustness with most state-of-the-art algorithms.Further,based on the precise pose estimation and tracking realized by our TAB-IOL,several formation control experiments are conducted for the group of fish-like robots.The results clearly demonstrate that our TAB-IOL lays a solid foundation for the coordination control of multiple fish-like robots in a real working environment.We believe our proposed method will facilitate the growth and development of related fields.

Intelligent Development Environment and Software Knowledge Graph

Software intelligent development has become one of the most important research trends in software engineering. In this paper, we put forward two key concepts -- intelligent development environment （IntelliDE） and software knowledge graph -- for the first time. IntelliDE is an ecosystem in which software big data are aggregated, mined and analyzed to provide intelligent assistance in the life cycle of software development. We present its architecture and discuss its key research issues and challenges. Software knowledge graph is a software knowledge representation and management framework, which plays an important role in IntelliDE. We study its concept and introduce some concrete details and examples to show how it could be constructed and leveraged.

LanePost:Lane-Based Optimal Routing Protocol for Delay-Tolerant Maritime Networks

Ship.to.ship, ship.to.shore radio links empowered by Wi Fi, Wi MAX etc have been recently exploited to build maritime multi.hop mesh networks to provide internet services to on.ship users. However, because of the mobility of the vessels/ships and the large inter.ship distances, nodes in the maritime network are frequently disconnected, forcing data communication in the maritime mesh networks to be opportunistic and delay.tolerant. In this paper, we present Lane Post, an optimization approach for maritime delay.tolerant routing protocol. We exploit the shipping lane information to predict the rendezvous opportunities of the ships to optimize the route selection in delay.tolerant routing. In particular, we show that when the shipping lane information is available, an opportunistic routing graph(ORG) for each ship can be constructed to predict its multi.hop data routing opportunities to the other ships or to the shore. Based on the ORG, we develop an optimal route protocol(i.e., Lane Post) for each ship to minimize its delay of multi.hop packet delivery via dynamic programming. We discussed the ways of collecting shipping lane information by centralized method or distributed method.The proposed Lane Post protocol was evaluated by ONE, an open.source delay.tolerant network simulator, which shows its dramatic performance improvement in terms of delay reduction compared to the state.of.the.art opportunistic routing protocols.

Checkpointing Scheme for Relevant Distributed Real-Time Tasks

A checkpointing scheme for relevant distributed real-time tasks which can be scheduled as a DAG is proposed. A typical algorithm, OSA, is selected for DAG scheduling. A new methods based a new structure, Scheduled Cluster Tree, is presented to calculate the slack time of each task in the task cluster. In the checkpointing scheme, the optimal checkpoint intervals which minimize the approximated failure probability are derived formally and validated experimentally. The complexity of approximated failure probability is quite small compared with that of the exact probability. Meanwhile, the consistency of the checkpointing is discussed also.

Thyroid function of twin-pregnant women in early pregnancy

Background: Serum human chorionic gonadotrophin (hCG) is higher in twin than that in singleton pregnancies. As hCG stimulates the thyroid to produce more free thyroxine (FT4), which may lead to decreased thyroid-stimulating hormone (TSH) levels, the reference ranges of thyroid-related indicators may differ between singleton and twin pregnancies in the first trimester. This study aimed to establish reference ranges for thyroid-related indicators in early twin pregnancies and to compare them with singleton pregnancies. Methods: Data of 820 twin-pregnant women were extracted from the established database of all pregnant women who delivered at Peking University First Hospital from October 2013 to May 2018;160 who met National Academy of Clinical Biochemistry criteria were included to establish TSH and FT4 reference ranges. We screened 480 (3:1 paired) women with singleton pregnancies from the same database as controls. The Mann-Whitney test for TSH and FT4 levels was applied for comparisons between singleton and twin pregnancies. Results: First-trimester reference ranges (4–12 gestational weeks) for twin pregnancies were: TSH 0.69 (0.01–3.35) mIU/L and FT4 16.38 (12.45–23.34) pmol/L. Median TSH was significantly lower at 7 to 12 gestational weeks than that at 4 to 6 gestational weeks (0.62 vs. 0.96 mIU/L, Z =-1.964, P = 0.049);FT4 was not significantly different between the two groups. Compared to singleton pregnancies, median TSH was significantly lower (0.69 vs. 1.27 mIU/L, Z =-6.538, P = 0.000), and FT4 was significantly higher (16.38 vs. 14.85 pmol/L, Z =-7.399, P = 0.000) in twin pregnancies in the first trimester. Conclusions: Specific reference ranges for thyroid-related indicators for twin pregnancies are needed to avoid a misdiagnosis of thyroid dysfunction. Moreover, establishment of separate reference ranges for 4 to 6 and 7 to 12 gestational weeks in twin pregnancies may be considered.

On the solution of Dirichlet problem of complex Monge-Ampère equation on Cartan-Hartogs domain of the second type

Complex Monge-Ampère equation is a nonlinear equation with high degree, so its solution is very difficult to get. How to get the plurisubharmonic solution of Dirichlet problem of complex Monge-Ampère equation on the Cartan-Hartogs domain of the second type is discussed by using the analytic method in this paper. Firstly, the complex Monge-Ampère equation is reduced to a nonlinear second-order ordinary differential equation (ODE) by using quite different method. Secondly, the solution of the Dirichlet problem is given in semi-explicit formula, and under a special case the exact solution is obtained. These results may be helpful for the numerical method of Dirichlet problem of complex Monge-Ampère equation on the Cartan-Hartogs domain.

Extending Interactive Web Services for Improving Presentation Level Integration in Web Portals

Presentation level integration now becomes an important and fast growing trend in enterprise computing Portal-based composite applications use portlet and interactive web service, which usually offers several portlets, as their basic constituents. Hence, portlet description and discovery are the key issues that have to be considered for the development of portal-based composite applications. This paper proposes a novel concept POI （Presentation Oriented Interface） to describe the presentation features of a portlet, so that interactive web services may be extended to facilitate the selection and interoperation of portlets. Portlet discovery can be effectively achieved based on the calculation of POI similarity that considers both type and structure similarity. Experiments show that the proposed approach can improve the satisfaction of portlet discovery, and also facilitate the portlet interoperation, thereby achieving better application integration at presentation level.

An application-semantics-based relaxed transaction model for internetware

An internetware application is composed by existing individual services, while transaction processing is a key mechanism to make the composition reliable. The existing research of transactional composite service （TCS） depends on the analysis to composition structure and exception handling mechanism in order to guarantee the relaxed atomicity. However, this approach cannot handle some application-specific requirements and causes lots of unnecessary failure recoveries or even aborts. In this paper, we propose a relaxed transaction model, including system mode, relaxed atomicity criterion, static checking algorithm and dynamic enforcement algorithm. Users are able to define different relaxed atomicity constraint for different TCS according to application-specific requirements, including acceptable configurations and the preference order. The checking algorithm determines whether the constraint can be guaranteed to be satisfied. The enforcement algorithm monitors the execution and performs transaction management work according to the constraint. Compared to the existing work, our approach can handle complex application requirements, avoid unnecessary failure recoveries and perform the transaction management work automatically.

Dynamic Parameters Cellular Automaton Model for Passengers in Subway

To simulate the passenger behavior in subway system, a Dynamic Parameters Cellular Automaton(DPCA) model is put forward in this paper. Pedestrian traffic flows during waiting, getting on or off, and traveling can be simulated. The typical scenario in Beijing Subway Line 13 is modeled to analyze the passenger behavior in subway system. By comparing simulation results with statistical ones, the correctness and practicality of the DPCA model are verified. At last, the additional results made by DPCA model can make contribution to passenger comfort analysis and pedestrian facility planning and guidance.

Real-time and generic queue time estimation based on mobile crowdsensing

People often have to queue for a busy service in many places around a city, and knowing the queue time can be helpful for making better activity plans to avoid long queues. Traditional solutions to the queue time monitoring are based on pre-deployed infrastructures, such as cameras and infrared sensors, which are costly and fail to deliver the queue time information to scattered citizens. This paper presents CrowdQTE, a mobile crowdsensing system, which utilizes the sensor-enhanced mobile devices and crowd hu- man intelligence to monitor and provide real-time queue time information for various queuing scenarios. When people are waiting in a line, we utilize the accelerometer sensor data and ambient contexts to automatically detect the queueing behav- ior and calculate the queue time. When people are not waiting in a line, it estimates the queue time based on the information reported manually by participants. We evaluate the perfor- mance of the system with a two-week and 12-person deploy- ment using commercially-available smartphones. The results demonstrate that CrowdQTE is effective in estimating queu- ing status.

Analyses for specific defects in Android applications:a survey

Android applications(APPS)are in widespread use and have enriched our life.To ensure the quality and security of the apps,many approaches have been proposed in recent years for detecting bugs and defects in the apps,of which program analysis is a major one.This paper mainly makes an investigation of existing works on the analysis of Android apps.We summarize the purposes and proposed techniques of existing approaches,and make a taxonomy of these works,based on which we point out the trends and challenges of research in this field.From our survey,we sum up four main findings:(1)program analysis in Android security field has gained particular attention in the past years,the fields of functionality and performance should also gain proper attention;the infrastructure that supports detection of various defects should be enriched to meet the industry’s need;(2)many kinds of defects result from developers’misunderstanding or misuse of the characteristics and mechanisms in Android system,thus the works that can systematically collect and formalize Android recommendations are in demand;(3)various program analysis approaches with techniques in other fields are applied in analyzing Android apps;however,they can be improved with more precise techniques to be more applicable;(4)The fragmentation and evolution of Android system blocks the usability of existing tools,which should be taken into consideration when developing new approaches.