Effective teaching pedagogy is important for the success of students. Basically, it involves various techniques such as face-to-face instruction, group work, problem solving, active learning and individual activity. The goal is to develop higher order thinking and enable meta-cognition, and to create an atmosphere to promote discussion and participation. In this study, students' view on a teaching pedagogy is presented in the context of a graduate-level course. This course is designed by incorporating a range of teaching methods so that students can pay attention throughout a class and comprehend subject matters easily. According to this study, in-class problem solving becomes the most popular among students. The study also shows that students prefer face-to-face classes compared to online or hybrid classes.

Crossfire Denial of Service (DDoS) is a new and organized type of attack to make the services of a target organization unavailable. The adversaries, in such attack, adveraremploy BOTs and decoy servers to flood critical links that are used to communicate with the target. In this paper, we propose an optimization framework, OPD (Optimized Packet Distributor), for distributing the packets in the most balanced way after a crossfire DDoS attack gets detected in a network. We formulate the network packet distribution problem as a non-linear link weight function and solved the optimization problem with a very efficient algorithm, Frank Wolf (FW). FW is the most efficient algorithm for solving convex set optimization problem. It achieves network equilibrium (or converges) with very few iterations. OPD will help the commonly used routing algorithm of Software Defined Network (SDN) by providing an optimized number of packets for each link. When a router sends a packet, it will follow the packet distribution proposed by OPD. We simulated a crossfire attack in NS2 simulator. The number of packets traveling in each link is collected for a given time frame from NS2. Based on this packet distribution, OPD proposes desired packet flows for the network. After evaluating the result of OPD, we have found that it can distribute the packets to the links that were less congested during the time of crossfire DDoS attack.

Cloud gaming, the newest entry in the online gaming world, leverages the well-known concept of cloud computing to provide real-time gaming services to players. The idea in cloud gaming is to capture the game events from players and transmit them to the cloud, process those events and run the game logic in the cloud, render the game scene as video in the cloud, and stream that video to the players. The advantage is that as long as the client can display video, which pretty much all smartphones, tablets, game consoles, desktops, laptops, and mobile devices today do, the user can play the game without installing it locally, and without needing to have a machine with high-grade 3-D graphics rendering and powerful computing hardware and software. This makes cloud gaming accessible to a huge market of mass consumers. While some variations of cloud gaming systems stream 3-D graphics, in addition to or instead of video, the great majority of cloud gaming implementations are video based. Using the well-known concept of software as a service, cloud gaming is also sometimes referred to as gaming as a service, which is already available as commercial products, such as Sony’s PlayStation Now, Ubitus’s GameNow, G-Cluster, Crytek’s GFACE, PlayGiga, and LiquidSky, to name a few. There are also many efforts concentrating specifically on the underlying technology behind cloud gaming, such as NVIDIA’s Grid, OTOY, CiiNow, Kalydo, and GamingAnywhere [4], the latter being the only open source and free technology. Microsoft is also exploring cloud gaming technologies, with recent successes such as its Kahawai project [1].

With the growing demand of mobile applications and games, one of the challenges is how to efficiently transmit the bulky 3D information to bandwidth- and computationally-limited mobile devices. In this paper, we propose two methods for improving the transmission delay of M3G-based 3D mobile game content over unreliable and congested networks. We introduce Object Mesh Similarity as a server side approach, in which we try to detect an alternative object with minimum complexities that is similar to the original object, and then transmit this reconstructed object, as well as Texture Stretching as a client-side approach, which leads to the efficient receipt of object textures. Our results show 35% to 70% improvement in the transmission delay of 3D textures.

The growing number of elderly population at home and abroad necessitates improved approaches to elderly care provision. Elders, often with cognitive and physical impairment, need assistance in their activities of daily living (ADLs), which is usually provided by human caregivers. As the demand for caregivers assistance increases, the shortage of traditional care resources becomes obvious. In this paper, we present the Virtual Caregiver (ViCare) framework that supports a human caregiver to monitor continuously the elderly by being aware of their surroundings. The ViCare system attempts to understand the elderly persons activities and contexts based on the data captured by the sensors placed in their environment and dynamically decides what services to provide them or whether there is a need to interrupt human caregiver depending on the type of activities. It not only minimizes the cognitive load of the human caregiver but also provides a seamless assistance to the elderly toward their improved health and well-being in their living environment. We conducted the experiments in an instrumented home environment and obtained positive results in terms of the satisfaction of the elderly, interaction event handling, caregivers acceptance and their engagement.

Design and implementation of an automated or a semi automated surveillance system is an active research area. Safety concerns of individuals have accelerated the research for identifying alarming human activities in public spaces like streets, shopping malls, airports, and others. But reliance on human operator for real-time actions can be inappropriate and expensive. On the other hand, demonstrating pragmatic scene of a surveillanced area with the help of a synthetic world can be effective that can guard operator's limitation. In this paper, we design a Decision Support Engine (DSE) coupled with a synthetic space to facilitate surveillance activities of operators. For this purpose, the detailed sensory data are processed and alarms are detected, classified and ranked according to the threat severity that follows some well-defined rules of the system. At the end, the identified alarming cases are marked and presented with the help of a synthetic environment in an elegant way so that the operators can take the right action in a specific security circumstance.

In this paper, we present a dynamic area of interest management for massively multiplayer online games (MMOG). Instead of mapping the virtual space to the area of interest (AOI), we scheme AOIs to the virtual space. This zoneless MMOG is the consequence of dynamic AOI that redeems the necessity of inter-AOI communication. In addition, the AOI maintenance cost is reduced significantly by assigning the maintenance responsibility to a subset of players for each AOI. Due to the integration of peer-to-peer communication model to the system, the scalability has improved. To satisfy the timing constraints, the projection of the underling network topology to the overlay network is more fruitful than building the overlay on the fly unintelligently. In response to this fact, the proposed communication model adapts a geometric algorithm which is usually used for minimax problem. The model is evaluated and justified through proper simulation.

In this paper, we present a new concept of distributed adaptation and P2P streaming supporting the expansion of context-aware mobile P2P systems. Here, we propose to adapt video contents in a distributed manner to address the peer heterogeneity. It also forms an overlay network and organizes video streaming sessions among the participating peers. We have followed a master-sender-driven approach (one-to-many), with the help of cooperative peers. The essential incentive behind this work is that with the modern computing capabilities, a single peer can carry out sufficient adaptation operations and stream media contents to other peers. Overall design and adaptation approach along with the performance evaluation is presented in brief.

State management is a fundamental requirement of multi-user applications like distributed simulations or networked games. The quality of the experience of such applications heavily depends on synchronous communication. The movement of an entity from one logical zone into another initiates reorganization of the peer-to-peer structure and eventually ruins synchronous interactions. The frequent nature of such event in the distributed simulations has significant impact on the performance and cannot be ignored. In this paper, we present a performance enhancement mechanism considering the physical attributes of the entities. We demonstrate that clustering the entities based on their physical characteristics or behavior significantly reduces peer- to-peer structural reformation penalties. The effectiveness of such clustering mechanism is simulated and analyzed in the context MMOG.

Distributed simulations that support a massive number of users typically divide the virtual world into zones that are managed by separate servers to evenly distribute resources and achieve scalability. However, such zoning restricts cross-zonal interactions and exposes the division of the world to the participating parties. Problems such as crowding one zone among others defeats the very purpose of interest management and makes geographic partitioning inefficient for modeling interactions. In this work, we have designed and implemented a visibility-driven approach to make the partitioning transparent to users. The effectiveness of this distributed architecture is tested through a prototype implementation. We also introduce a novel idea to dynamic load balancing that can be achieved in real-time without modifying the communication architecture. By increasing the granularity of the partitioning and providing a layered approach to zoning, transient crowding can be handled by adoptively dispersing parts of the crowded zone to adjacent servers.

In this paper, we present a graph-theoretic framework for provisioning overlay network based multimedia distribution services to a diverse set of receivers. Considering resource limitations and exploiting geographical positions, it greedily constructs degree-constrained minimum-cost connected graph to manipulate the topology to a significant extent by selecting mesh neighbors and changing the metrics. Data delivery paths and forwarding nodes are chosen using the dominating set. The minimal cardinality of the dominating set reduces the system's dependency on end-hosts. Simulation is used to demonstrate that the framework is more robust and responsive to tree partitions and suitable for multi-source multimedia applications.

Synchronous communication is a primary concern for multi-user virtual environments like Massively Multiplayer Online Games (MMOGs). Most of the MMOGs offer discrete view for the avatars and follow logical zone layout for easy state management. The avatar movement, from one logical zone to another, causes reorganization at the P2P overlay structure. Its recurrent nature along with unintelligent zone crossing approaches eventually hampers synchronous communication. In this paper, we present performance enhancement mechanisms to reduce P2P overlay reorganization penalties based on avatars ’ physical characteristics. Avatars ’ unpredictable movement around the zone boundaries also incur repeated connections and disconnections either among the zone masters or among the multiple peers in the overlay networks. Interest driven zone crossing, dynamic shared region between adjacent zones, and clustering of the entities based on their attributes significantly alleviates these problems and also provides continuous view and seamless region crossing to players. The technical contribution of this paper is to present the effectiveness of object clustering mechanism and interest driven zone crossing with dynamic shared region between each adjacent zones to enhance the gaming experience of MMOG players or users of other types of networked virtual environments (VE).

IP multicasting is the most efficient way to perform group data distribution, as it eliminates traffic redundancy and improves bandwidth utilization. Application layer multicast (ALM) has been proposed to overcome some of the limitations in IP multicasting such as scalability and deployability. Limited computing power, scarcity of bandwidth and end-host's reluctance to share bandwidth make ALM difficult to spread. In this paper, we keep eye to those problems and present an ALM that scrutinizes the commitment of the ALM nodes. Failure to provide quality of service agreement triggers performance penalty for the node in concern. Thus, every node has an obligation to its descendants; as a result, a nice collaboration among the end-hosts is achieved for group communication. It has good performance for content distribution, as it reflects physical network topology onto the overlay network constructed by the end-hosts. Tree refinement and backup path strategies are taken to better satisfy heterogeneous QoS requirements