OSGi框架下基于LDAP的异构遥感服务调用机制研究

针对异构遥感算法服务集成方法在元数据和生命周期管理方面的不足,提出了在OSGi框架下基于LDAP的异构服务调用机制。该机制设计了一个异构服务代理,将异构服务封装为OSGi bundle服务,实现服务生命周期管理,并结合LDAP技术,实现异构服务元数据管理;同时引入工作流引擎技术,搭建了一个异构服务交互调用的原型系统。通过遥感NDVI产品生产实验表明,该方法不仅能灵活地调用多种异构的遥感算法服务,且能有效的管理服务元数据及其生命周期。最后性能分析表明,该方法也为遥感数据分布式处理提供了一种有效的解决方案。     

Remote method invocation as a first-class citizen

The classical remote method invocation (RMI) mechanism adopted by several object-based middleware is black-box in nature, and the RMI functionality, i.e., the RMI interaction policy and its configuration, is hard-coded into the application. This RMI nature hinders software development and reuse, forcing the programmer to focus on communication details often marginal to the application being developed. Extending the RMI behavior with extra functionality is also a very difficult job, because added code must be scattered among the entities involved in communications. This situation could be improved by developing the system in several separate layers, confining communications and related matters to specific layers. As demonstrated by recent work on reflective middleware, reflection represents a powerful tool for realizing such a separation and therefore overcoming the problems referred to above. Such an approach improves the separation of concerns between the communication-related algorithms and the functional aspects of an application. However, communications and all related concerns are not managed as a single unit that is separate from the rest of the application, which makes their reuse, extension, and management difficult. As a consequence, communications concerns continue to be scattered across the meta-program, communication mechanisms continue to be black-box in nature, and there is only limited opportunity to adjust communication policies through configuration interfaces. In this paper we examine the issues raised above, and propose a reflective approach specially designed to open up the RMI mechanism. Our proposal consists of a new reflective model, called multi-channel reification, that reflects on and reifies communication channels, i.e., it renders communication channels first-class citizens. This model is designed both for developing new communication mechanisms and for extending the behavior of communication mechanisms provided by the underlying system. Our approach is embodied in a framework called mChaRM, whisch is described in detail in this paper.Received: December 2001, Accepted: April 2003, Correspondence to: Walter Cazzola, c|o DISI, University of Genova, Via Dodecaneso 35. 16146, Genova, Italy. Fax + 39-010-353-6699)     

基于Android手机与远程PC的UDP文件传输机制

介绍一种Android手机与PC间文件传输的方法及其实现技术.通过分析Android SDK和Windows SDK中相关API接口,实现Android手机应用软件与PC的Windows软件之间的UDP协议文件传输.该机制在手机端采用Eclipse并运用java语言开发,在PC端采用Visual C++并运用C语言开发,同时在机制中增加了各种改进UDP协议的算法.实验结果表明,该机制提高了UDP协议传输的效率和可靠性,能够很好实现文件在手机与PC间的传输.     

Modules,objects and distributed programming: Issues in RPC and remote object invocation

Distributed programming can be greatly simplified by language support for distributed communication, such as that provided by remote procedure call (RPC) or remote object invocation. This paper examines design and implementation issues in these systems, and focuses on the influence of the communication system on a distributed program. To make the discussion concrete, we introduce a single application as implemented in two environments: Modula-2+, an extension of Modula-2 with RPC, and Emerald, an object-based language that supports remote object invocation. We show that small differences in the implementation of the communication system can have a significant impact on how distributed applications are structured.     

PRESS: a clustered server based on user-level communication

In this paper, we propose and evaluate a cluster-based network server called PRESS. The server relies on locality-conscious request distribution and a standard for user-level communication to achieve high performance and portability. We evaluate PRESS by first isolating the performance benefits of three key features of user-level communication: low processor overhead, remote memory accesses, and zero-copy transfers. Next, we compare PRESS to servers that involve less intercluster communication, but are not as easily portable. Our results for an 8-node server cluster and five WWW traces demonstrate that user-level communication can improve performance by as much as 52 percent compared to a kernel-level protocol. Low processor overhead, remote memory writes, and zero-copy all make nontrivial contributions toward this overall gain. Our results also show that portability in PRESS causes no throughput degradation when we exploit user-level communication extensively.     

Boosting: a classification method for remote sensing

This article sets out to demonstrate how boosting can serve as a supervised classification method, and to compare its results with those of conventional methods. The comparison begins with a theoretical example in which several criteria are varied: number of pixels per class, overlapping (or not) of radiometric values between classes, and presence and absence of spatial structuring of classes within the geographical space. The results are then compared with a real case study of land cover based on a multispectral SPOT image of the Sousson catchment area (South of France). It is seen that (1) maximum likelihood gives better results than boosting when the radiometric values for each class are clearly separated. This advantage is lost as the number of pixels per class increases; (2) boosting is systematically better than maximum likelihood in the event of overlapping radiometric variable classes, whether or not there is a spatial structure.     

DApriori：一种基于Apriori的Android恶意应用检测方法

目前很少有研究者使用有关联的静态与动态相结合的方式检测Android恶意应用,多数静态分析方法考虑具体代码运行流程,计算复杂度较高,而单纯的动态检测方法占用Android系统资源,大大降低手机的运行速度。本文提出DApriori算法,能够有效的检测出Android恶意应用。DApriori算法分别计算恶意应用样本与良性应用样本权限关联规则,对比两种样本得到的用户权限之间的差异性,并使用恶意样本得到的关联规则对一定的混合样本进行检测,实验结果表明,该算法能够有效地检测出Android恶意应用,并将关联规则应用于Android恶意应用动态检测中。     

Correction to: A decentralized honeypot for IoT Protocols based on Android devices

International Journal of Information Security -     

ASEHM: a new transmission control mechanism for remote rendering system

Digital 3D models have emerged as a new type of multimedia following sound, image and video. This media type has been distributed and processed widely on desktop PCs. However, processing 3D models on mobile devices is more difficult, mainly due to their physical constraints. Though the remote rendering framework is able to make up for some deficiencies, previous methods based on this framework suffered from high transmission frequency, which just imposes a high power demand on mobile devices’ already limited battery life. In this paper, a new transmission control method, Adaptive Splitting and Error Handling Mechanism, is proposed to be integrated with canonical remote rendering system. Our mechanism is able to reduce transmission frequency by trading transmission with splitting operations. According to relevant research findings, reducing frequency will result in a decline in power consumption. Finally, the effectiveness of our method in terms of frequency reduction is validated by comparison with state of the art method.     

Rajdoot: a remote procedure call mechanism supporting orphandetection and killing

Rajdoot is a remote procedure call (RPC) mechanism with a number of fault tolerance capabilities. A discussion is presented of the reliability-related issues and how these issues have been dealt with in the RPC design. Rajdoot supports exactly-once semantics with call nesting capability, and incorporates effective measures for orphan detection and killing. Performance figures show that the reliability measures of Rajdoot impose little overhead     

FastUDP: a highly scalable user-level UDP framework in multi-core systems for fast packet I/O

The Journal of Supercomputing - Nowadays, many applications, e.g., network routers, distributed data process engines, firewall, need to transfer packets at linear rate. With the increasing data...     

DroidChain: A novel Android malware detection method based on behavior chains

The drastic increase of Android malware has led to strong interest in automating malware analysis. In this paper, to fight against malware variants and zero-day malware, we proposed DroidChain: a method combining static analysis and a behavior chain model. We transform the malware detection problem into more accessible matrix form. Using this method, we propose four kinds of malware models, including privacy leakage, SMS financial charges, malware installation, and privilege escalation. To reduce time complexity, we propose the WxShall-extend algorithm. We had moved the prototype to GitHub and evaluate using 1260 malware samples. Experimental malware detection results demonstrate accuracy, precision, and recall of 73%–93%, 71%–99%, and 42%–92%, respectively. Calculation time accounts for 6.58% of the well-known Warshall algorithm’s expense. Results demonstrate that our method, which can detect four kinds of malware simultaneously, is better than Androguard and Kirin.     

A remote sensing-based method for drought monitoring using the similarity between drought eigenvectors

ABSTRACT

The land surface temperature (LST) and vegetation growth status are two direct indicators of drought. In this study, we selected the LST index and vegetation index to construct drought eigenvectors, then proposed a new remote sensing drought index to assess the drought severity by calculating the similarity between the drought eigenvector of the target pixel and the drought eigenvector under an extremely wet state. Considering the different responses of various objects to drought, the drought eigenvectors of different land cover types were established. The results showed that the Temperature-Vegetation Water Stress Index (T-VWSI) were highly correlated with the measured relative soil moisture (RSM). The correlation coefficients (r) between the T-VWSI and 20-cm RSM reached 0.81, 0.77, and 0.78 in May, June, and July, respectively. Therefore, the T-VWSI is a promising drought index that will play an important role in drought monitoring.     

Fast fabrication of microfluidic devices using a low-cost prototyping method

Conventional ways to produce microfluidic devices cost a lot due to the requirements for cleanroom environments and expensive equipment, which prevents the wider applications of microfluidics in academia and in industry. In this paper, a dry film photoresist was utilized in a simple way to reduce the fabrication cost of microfluidic masters. Thus, a fast prototyping and fabrication of microstructures in polydimethylsiloxane microchips through a replica molding technology was achieved in a low-cost setting within 2.5 h. Subsequently, major manufacturing conditions were optimized to acquire well-resolved microfluidic molds, and the replicated microchips were validated to be of good performance. A T-junction channel microchip was fabricated by using a dry film master to generate water droplets of uniform target size. Meanwhile, a gated injection of fluorescein sodium and a contactless conductivity detection of Na⁺ were both performed in a crosslink channel microchip via capillary electrophoresis, in other words, this fast prototyping and fabrication method would be an efficient, economical way to embody structural design into microfluidic chips for various applications.     

Energy inefficiency diagnosis for Android applications: a literature review

Android applications are becoming increasingly powerful in recent years. While their functionality is still of paramount importance to users, the energy efficiency of these applications is also gaining more and more attention. Researchers have discovered various types of energy defects in Android applications, which could quickly drain the battery power of mobile devices. Such defects not only cause inconvenience to users, but also frustrate Android developers as diagnosing the energy inefficiency of a software product is a non-trivial task. In this work, we perform a literature review to understand the state of the art of energy inefficiency diagnosis for Android applications. We identified 55 research papers published in recent years and classified existing studies from four different perspectives, including power estimation method, hardware component, types of energy defects, and program analysis approach. We also did a cross-perspective analysis to summarize and compare our studied techniques. We hope that our review can help structure and unify the literature and shed light on future research, as well as drawing developers' attention to build energy-efficient Android applications.     

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.     

USBWall: A novel security mechanism to protect against maliciously reprogrammed USB devices

Universal Serial Bus (USB) is a popular choice of interfacing computer systems with peripherals. With the increasing support of modern operating systems, it is now truly plug-and-play for most USB devices. However, this great convenience comes with a risk that can allow a device to perform arbitrary actions at any time while it is connected. Researchers have confirmed that a simple USB device such as a mass storage device can be disguised to have an additional functionality such as a keyboard. An unauthorized keyboard attachment can compromise the security of the host by allowing arbitrary keystrokes to enter the host. This undetectable threat differs from traditional virus that spreads via USB devices due to the location where it is stored and the way it behaves. We propose a novel way to protect the host via a software/hardware solution we named a USBWall. USBWall uses BeagleBone Black (BBB), a low-cost open-source computer, to act as a middleware to enumerate the devices on behalf of the host. We developed a program to assist the user to identify the risk of a device. We present a simulated USB device with malicious firmware to the USBWall. Based on the results, we confirm that using the USBWall to enumerate USB devices on behalf of the host eliminates risks to the hosts.     

Design of an auto-focusing actuator with a flexure-based compliant mechanism for mobile imaging devices

There is increasing consumer’s demand for high-quality and high-performance mobile imaging devices. In this paper, an auto-focusing (AF) actuator with a flexure hinge that uses the electromagnetic (EM) circuit of a voice coil motor was designed and evaluated. The flexure hinge was designed by using finite element analysis. The EM circuit was designed based on the structural stiffness of the device. The EM circuit was analyzed using the design of experiments procedure. Based on the results, the effective design parameters were selected, and improvements were made to the design. Finally, a prototype of the AF actuator was manufactured, and the feasibility and performance of the actuator with the flexure hinge were verified experimentally. The experimental results indicated that the proposed actuator performed adequately and satisfied the design requirements.