Sharif Digital Repository

Following the expansion of Internet, many software were produced that could launch through Internet without prior installation on computers. This included game software and software that deal with financial affairs. These softwares are mainly in Java language and can be found on web pages as Java Applets. Some software owners want that their products only able to execute through their own web pages so that no one could put them on other web pages. In this paper, a new method has been presented to protect Java Applets from copying by using "Steganography in HTML web pages" method. In this method, a special 8-character string is hidden in the HTML page by a secret key. The string and the... 

Establishing hidden communication is an important subject of discussion that has gained increasing importance nowadays with the development of the Internet. One of the methods introduced for establishing hidden communication is steganography. Methods of steganography have been mostly applied on images while the major characteristic of these methods is the change in the structure and features of the images so as not to be identifiable by human users. However, on the other hand, many methods have been proposed for breaking and extracting information (steganalysis) for these methods. This paper presents a method for hiding information in images by changing the appearance of the picture instead... 

In this study, a hydrophilic metal-organic framework (MOF) was applied to improve the performance of a cellulosic membrane for forward osmosis (FO) desalination application. The characterization results confirmed that the MOF particles existed within the matrix of the modified membrane. The MOF loading led to adjustment of the membranes in terms of overall porosity, pore inter-connectivity and hydrophilicity. These features caused an improvement in the pure water permeability (72%) and reduce the structural parameter of the modified membrane to 136 μm. The FO water flux of the modified membrane enhanced by about 180% compared to an unmodified membrane, without decreasing its selectivity. FO... 

Using an FPGA as a hardware accelerator has been prevalent, to speed up compute intensive workloads. However, employing an accelerator in virtualized environment enhances complexity, because accessing the accelerator from virtual machines has significant overhead and sharing it needs some considerations. We have implemented adequate infrastructure to share an FPGA-based accelerator between multiple virtual machines with negligible access overhead which dynamically implements virtual machines' accelerators. In our architecture each user process from a virtual machine can directly access the FPGA over PCIe link and reconfigure its accelerator in the specified part of FPGA at run-time. The... 

Nowadays, many daily human activities such as education, commerce, talks, etc. are carried out through the Internet. In cases such as the registering in websites, some hackers write programs to make automatic false enrolments which waste the resources of the website while this may even stop the entire website from working. Therefore, it is necessary to tell apart human users from computer programs which is known as CAPTCHA (Completely Automated Public Turing test to tell Computers and Human Apart). CAPTCHA methods are mainly based on the weak points of OCR (Optical Character Recognition) systems while using them are undesirable to human users and esp. difficult in tools such as PDA's or... 

Delivering first aid before transferring patients to hospital is among keys to survival. Moreover, calling the emergency center as soon as possible and providing brief information about the patient are helpful for the emergency center to dispatch specialized medical team and equipments proportionate to the conditions of the patient. Mobile phone is a device which many people use and always carry with them. One more thing is that SMS (Short Message Service) stands as a favorite service in mobile network, used to exchange short messages and featuring low cost, non-stop lines of dispatch, possibilities for offline work and so forth. This paper puts forward procedures of calling an emergency... 

Conveying information secretly and establishing hidden relationship has been of interest since long past. Text documents have been widely used since very long time ago. Therefore, we have witnessed different method of hiding information in texts (text steganography) since past to the present. In this paper we introduce a new approach for steganography in Persian and Arabic texts. Considering the existence of too many points in Persian and Arabic phrases, in this approach, by vertical displacement of the points, we hide information in the texts. This approach can be categorized under feature coding methods. This method can be used for Persian/Arabic Watermarking. Our method has been... 

Exceptions are an indispensable part of the software development process. However, developers usually rely on imprecise results from a web search to resolve exceptions. More specifically, they should personally take into account the context of an exception, then, choose and adapt a relevant solution to solve the problem. In this paper, we present Exception Tracer, an Eclipse plug in that helps developers to resolve exceptions with respect to the stack trace in Java programs. In particular, Exception Tracer automatically provides candidate solutions to an exception by mining software systems in the Source Forge, as well as listing relevant discussions about the problem from the Stack Overflow... 

We report the nanoporous Ag2O based on the copper terephthalate metal–organic frameworks (Ag2O/MOF) photocatalyst. Ag2O/MOF nanostructure was formed via oxygen treatment of Ag/MOF nanoparticles. The resulting Ag2O/MOF photocatalysts were characterised by various techniques. Results showed that the synthesised Ag2O/MOF nanocomposite exhibited dramatic separation of photoinduced electron/hole and excellent photodegradation activity under visible light irradiation. The degradation rate of acid blue 92 using Ag2O/MOF nanocomposite is found to be higher than that using pure MOF and Ag/MOF. It was divulged that the photodegradation rate is increased by oxygen treatment of Ag in Ag/MOF structure.... 

The necessity and significance of improving the energy efficiency of cloud implementations have increased due to the rapid growth and proliferation of cloud computing services around the world. Virtual machines (VMs) comprise the backend of most, if not all, cloud computing services. Several VMs are often consolidated on a physical machine to efficiently utilize its resources. In this paper, we take into account the cooling and network structure of the datacenter host ing the physical machines when consolidating the VMs so that fewer racks and routers are employed, without compromising the service-level agreements; consequently, idle routing and cooling equipment can be turned off in order... 

In this paper, a practical educational tool based on Java programming is described. The approach is based on using a fully interactive graphical user interface for teaching cipher algorithms. As an example, a transposition cipher is covered, where students can try different keys and observe the effect of parameters such as key length, choice of letters for the key on the ciphertext. At the same time, the process of breaking the cipher algorithm (cryptanalysis) is rendered possible by students injecting known plaintext. The developed program offers an option where it tries systematically all keys (brute force) to break the cipher. Being extendable, the platform is thought to be able to play a... 

Object-oriented application frameworks, such as Java Swing, provide reusable code and design for implementing domain-specific concepts, such as Context Menu, in software applications. Hence, use of such frameworks not only can decrease the time and the cost of developing new software applications, but also can increase their maintainability. However, the main problems of using object-oriented application frameworks are their large and complex APIs, and often incomplete user manuals. To mitigate these problems, developers often try to learn how to implement their desired concepts from available sample applications. Nonetheless, this introduces another hard and time-consuming challenge which... 

To perform software maintenance, developers must have a relatively good understanding of the program's source code, which is often written by other developers. Code summaries, which describe a program's entities (for example, its methods), help developers better comprehend code more quickly. However, generating code summaries can be challenging. To mitigate this problem, CrowdSummarizer exploits crowdsourcing, gamification, and natural-language processing to automatically generate high-level summaries of Java program methods. Researchers have implemented it as an Eclipse plug-in together with a Web-based code summarization game that can be played by the crowd. Two empirical studies... 

In this study, zeolitic imidazolate framework (ZIF-8) as a metal-organic framework (MOF) and its hybrid nanocomposites based on graphene oxide (GO) and carbon nanotubes (CNTs) were synthesized by facile method at an ambient temperature. The sufficiency of GO and CNT substrates as the main components of the composites to grow nanoscale MOFs and increase dispersive forces were investigated. The characteristics of the MOF and hybrid nanocomposites were studied using FTIR, SEM, XRD, BET and TGA techniques. The prepared nanomaterials applied as adsorbents to remove malachite green (MG) as a cationic dye from colored wastewater. The removal rates of the hybrid nanocomposites were greater than that... 

Mobile phone and Internet technologies have progressed along each other. The importance of both these technologies has resulted in the creation of a new technology for establishing wireless Internet connection through mobile phone, known as Wireless Application Protocol (WAP). However, considering the importance of the issue of data security and especially establishing hidden communications, many methods have been presented. In the meanwhile, steganography is a relatively new method. In this paper, a method for hidden exchange of data has been presented by using steganography on WML pages (WML stands for Wireless Markup Language, which is a language for creating web pages for the WAP). The... 

There are many websites specially designed for mobile phones. Some hackers write automated programs to abuse these website services and waste the website resources. Therefore, it is necessary to distinguish between human users and computer programs. Methods known for achieving this are known as CAPTCHA (Completely Automated Public Turing test to tell Computers and Human Apart). CAPTCHA methods are mainly based on the weaknesses of OCR (Optical Character Recognition) systems and ask the user to type a word. So using them is difficult in tools such as PDAs (Personal Digital Assistant) or mobile phones that lack a complete keyboard. In this paper, a new CAPTCHA system is proposed for... 

JML is a behavioral interface specification language which has Java as its target implementation language. It combines the idea of using Java expressions from Eiffel language with the model-based approach to specify a program. Refinement calculus is a framework to produce executable code from a specification by preserving the correctness of programs. In this paper some constructs of JML concerning object creation, feature call, exceptional behavior and concurrency constructs are studied and some refinement rules are proposed to obtain an object oriented code in Java from a JML specification containig these constructs. The correctness of these rules is proved by weakest precondition predicate... 

One of the services used in mobile phone is the short message service (SMS) which is widely used by the public in all parts of the world especially in Asia and Europe. This service enables people to write and exchange short messages via mobile phone. Due to the limited size of SMS, lack of a proper keyboard on the mobile phone and to improve the speed of typing, new abbreviations have been invented for different words and phrases which has lead to the invention of a new language called SMS-Textlng. One of the main issues in communication is information security and privacy. There are many methods for secret communication and many researchers are working on steganography. In steganography the... 

Invention of the Internet and its spread in the world changes various aspects of human life. In addition, Internet changed human relations. Chat is one of the new aspects which invented after the Internet and is welcomed by users, especially by young people. In chat rooms, people talk with each other using text messages. Because of the need for quick typing of the word and also because of the high amount of sentences which is exchanged between users, new abbreviations are invented for various words and phrases in chat rooms. This new language is known as SMS-Texting. On the other hand, the issue of safety and security of information and especially secret relationships has led to the... 

After rapid growth of the Internet, establishing hidden communication is an important subject of security that has gained increasing importance. One of the methods for establishing hidden communication is steganography. On the other hand with the expanding the use of mobile phones mobile telecommunication companies starting to add additional features to their mobile phones such as MMS (Multimedia Messaging Service) in order to attract more customers. Considering above statements, steganography in MMS messages is a good solution for establishing hidden communication. In this paper a new method for steganography in MMS messages using both text and image steganography methods is presented. This...