Seedemu: The Seed Internet Emulator

I studied and experimented with the idea of building an emulator for the Internet. While there are various already available options for such a task, none of them takes the emulation of the entire Internet as an important feature in mind. Those emulators and simulators can handle small-scale networks pretty well, but lacks the ability to handle large-size networks, mainly due to: - Not being able to run many nodes, or requires very powerful hardware to do so,- Lacks convenient ways to build a large emulation, and - Lacks reusability: once something is built, it is very hard to re-use them in another emulation I explored, in the context of for-education Internet emulators, different ways to overcome the above limitations. I came up with a framework that enables one to create emulation using code. The framework provides basic components of the Internet. Some examples include routers, servers, networks, Internet exchanges, autonomous systems, and DNS infrastructure. Building emulation with code means it is easy to build emulation with complex topologies since one can make use of the common control structures like loops, subroutines, and functions. The framework exploits the idea of ``layers.\u27\u27 The idea of ``\emph{layers}\u27\u27 can be seen as an analogy of the idea of ``layers\u27\u27 in image processing software, in the sense that each layer contains parts of the image (in this case, part of the emulation), and need to be ``rendered\u27\u27 to obtain the resulting image. There are two types of layers, base layers and service layers. Base layers describe the ``base\u27\u27 of the topologies, like how routers, servers, and networks are connected, how autonomous systems are peered with each other; service layers describe the high-level services on the Internet. Examples of services layers are web servers, DNS servers, ethereum nodes, and botnet nodes. No layers are tied to any other layers, meaning each layer can be individually manipulated, exported, and re-used in another emulation. One can build an entire DNS infrastructure, complete with root DNS, TLD DNS, and deploy it on any base layer, even with vastly different underlying topologies. The result of the rendered layer is a set of data structures that represents the objects in a network emulation, like host, router, and networks. These representations can then be ``compiled\u27\u27 into something that one can execute using a compiler. The main target platform of the framework is Docker. The source of the SEEDEMU project is publicly available on Github: https://github.com/seed-labs/seed-emulator

Real-time Monitoring for the Next Core-Collapse Supernova in JUNO

Core-collapse supernova (CCSN) is one of the most energetic astrophysical events in the Universe. The early and prompt detection of neutrinos before (pre-SN) and during the SN burst is a unique opportunity to realize the multi-messenger observation of the CCSN events. In this work, we describe the monitoring concept and present the sensitivity of the system to the pre-SN and SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is a 20 kton liquid scintillator detector under construction in South China. The real-time monitoring system is designed with both the prompt monitors on the electronic board and online monitors at the data acquisition stage, in order to ensure both the alert speed and alert coverage of progenitor stars. By assuming a false alert rate of 1 per year, this monitoring system can be sensitive to the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos up to about 370 (360) kpc for a progenitor mass of 30$M_{\odot}$ for the case of normal (inverted) mass ordering. The pointing ability of the CCSN is evaluated by using the accumulated event anisotropy of the inverse beta decay interactions from pre-SN or SN neutrinos, which, along with the early alert, can play important roles for the followup multi-messenger observations of the next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure

Potential of Core-Collapse Supernova Neutrino Detection at JUNO

JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve

Detection of the Diffuse Supernova Neutrino Background with JUNO

As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO

c 2013 NSP Natural Sciences Publishing Cor. Predictive Web Service Monitoring using Probabilistic Model Checking

Abstract: Web service is vulnerable to stochastic failures due to the changeful Internet environment, which will seriously impact the reliability of business-critical applications. Web service must adapt to these changes. This paper studies the monitoring issue of Web service and proposes a predictive service monitoring approach to support service-oriented software dynamic evolutions. It aims to ensure that Web service is high-quality at runtime. Considering functional and non-functional requirements, we employ probabilistic model checking technique to quantitatively verify the interactive behaviour of Web service. However, limited by time and memory, frequently performing probabilistic model checking is not a high-efficiency solution to monitor Web service. Thus, forecasting the reliability becomes an important way to enhance the performance of Web service monitoring, by which we can put forward dynamic reconfigurations before the exception occurs. For this purpose, according to the historical probability values of Web service reliability recorded in monitoring phase, we adopt the mathematical statistics, unary linear regression analysis method, to predict the probability value of reliability based on invocation duration time. Finally, a case study is discussed and experiment results demonstrate the applicability and effectiveness of our approach

A Novel Approach to Dynamically Construct User Navigation-Oriented Quantitative Model for Web Service

Web service is considered as one of computational resources available on network, which has become a popular paradigm to develop platform-independent applications. However, due to the diverse-grained, non-determinism, and timeliness natures of Web service, it is not surprising thatWeb-based service application frequently experiences problems, such as unreachable pages and reduced responsiveness. To address this problem, the primary task is to verify and testWeb engineering for trustworthy, in which the quantitative model generation of service behaviors plays a critical role during software life cycle, especially business processes verification. In this paper, navigation behaviors between Web application and users are formalized as service process. Then, the navigation model corresponding to service process is extended with non-functional specifications by using probability matrix and time constraint pair method, mainly random natures and time features. Finally, the comprehensive model and its parallel composition are introduced to cope with more complex service interactions modeling. In conclusion, our navigation-oriented quantitative model specified with time constrains and probability specifications gives a solution to dynamic features extraction for constructing hybrid model of Web service

Test Sequence Reduction of Wireless Protocol Conformance Testing to Internet of Things

Wireless communication protocols are indispensable in Internet of Things (IoT), which refer to rules and conventions that must be followed by both entities to complete wireless communication or service. Wireless protocol conformance testing concerns an effective way to judge whether a wireless protocol is carried out as expected. Starting from existing test sequence generation methods in conformance testing, an improved method based on overlapping by invertibility and multiple unique input/output (UIO) sequences is proposed in this paper. The method is accomplished in two steps: first, maximum-length invertibility-dependent overlapping sequences (IDOSs) are constructed, then a minimum-length rural postman tour covering the just constructed set of maximum-length IDOSs is generated and a test sequence is extracted from the tour. The soundness and effectiveness of the method are analyzed. Theory and experiment show that desirable test sequences can be yielded by the proposed method to reveal violations of wireless communication protocols in IoT

Location-Based Test Case Prioritization for Software Embedded in Mobile Devices Using the Law of Gravitation

Considering that some intelligent software in mobile devices is related to location of sensors and devices, regression testing for it faces a major challenge. Test case prioritization (TCP), as a kind of regression test optimization technique, is beneficial to improve test efficiency. However, traditional TCP techniques may have limitations on testing intelligent software embedded in mobile devices because they do not take into account characteristics of mobile devices. This paper uses a smart mall as a scenario to design a novel location-based TCP technique for software embedded in mobile devices using the law of gravitation. First, test gravitation is proposed by applying the idea of universal gravitation. Second, a specific calculation model of test gravitation is designed for a smart mall scenario. Third, how to create a faulted test case set is designed by the pseudocode. Fourth, a location-based TCP using the law of gravitation algorithm is proposed, which utilizes test case information, fault information, and location information to prioritize test cases. Finally, an empirical evaluation is presented by using one industrial project. The observation, underlying the experimental results, is that our proposed TCP approach performs better than traditional TCP techniques. In addition, besides location information, the level of devices is also an important factor which affects the prioritization efficiency