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Adapting the Streaming Video Based on the Estimated Position of the Region of Interest
No full textStreaming real time video over wireless networks cannot guarantee that all the
frames could meet their deadlines. Wireless networks may suffer from bandwidth
limitations. To reduce the streaming data over wireless networks, we propose a
technique to identify, and extract the Region Of Interest (ROI), and drop the
non-ROI from the frames that are between the reference frames. The Sum of
Absolute Differences (SAD) will compute the consecutive video frames to
identify the ROI as it considered the most motion and important region. The
reconstruction mechanism to the non-ROI is performed on the mobile side by
applying linear interpolation between the reference frames. We evaluate the
proposed approach by using Mean Opinion Score (MOS) measurements. MOS are used
to evaluate the two scenarios with equivalent encoding size, where the users
observe the first scenario with a low bit rate for the original videos, while
for the second scenario the users observe our proposed approach. The results
show that our technique significantly reduces the amount of data, while the
reconstruction mechanism provides acceptable video quality to the mobile
viewers
Fostering Cross-site Coordination through Awareness: An investigation of state-of-the-practice through a focus group study
No full textAwareness and shared knowledge are important ingredients of successful
coordination in software engineering projects, and especially when team members
are distributed. Although various coordination mechanisms and knowledge sharing
recommendations for cross-site collaboration have been proposed, spreading
awareness among distributed team members in a global software project has
proven to be challenging in practice. In this paper we discuss our findings
from conducting three focus groups on knowledge management in global software
collaborations in two international organizations. We discuss various awareness
needs in globally distributed collaborations that were not addressed by the
organizations, and conclude that best practices and tools proposed in related
research are not widely used. On the basis of our empirical findings we suggest
future research directions and share recommendations for practical
improvements
A consolidated process for software process simulation: State of the Art and Industry Experience
No full textSoftware process simulation is a complex task and
in order to conduct a simulation project practitioners require
support through a process for software process simulation
modelling (SPSM), including what steps to take and what
guidelines to follow in each step. This paper provides a
literature based consolidated process for SPSM where the
steps and guidelines for each step are identified through a
review of literature and are complemented by experience from
using these recommendations in an action research at a large
Telecommunication vendor. We found five simulation processes
in SPSM literature, resulting in a seven-step process. The
consolidated process was successfully applied at the studied
company, with the experiences of doing so being reported
Instability of water jet: Aerodynamically induced acoustic and capillary waves
No full textHigh-speed water jet cutting has important industrial applications. To further
improve the cutting performance it is critical to understand the theory behind
the onset of instability of the jet. In this paper, instability of a water jet
flowing out from a nozzle into ambient air is studied. Capillary forces and
compressibility of the liquid caused by gas bubbles are taken into account,
since these factors have shown to be important in previous experimental
studies. A new dispersion equation, generalizing the analogous Rayleigh
equation, is derived. It is shown how instability develops because of
aerodynamic forces that appear at the streamlining of an initial irregularity
of the equilibrium shape of the cross-section of the jet and how instability
increases with increased concentration of gas bubbles. It is also shown how
resonance phenomena are responsible for strong instability. On the basis of the
theoretical explanations given, conditions for stable operation are indicated
N-dimensional fault detection and operational analysis with performance metrics
No full textA district heating consumer substation is a complex
entity, consisting of a range of interacting components
such as valves, pumps, heat exchangers and control
systems. The energy efficiency of a consumer sub-
station is dependent on several things, e.g. settings of
the control system, dimensions and operational
behaviour of hardware and accumulation of sediments
in the heat exchanger. Visualizing this operational
functionality of consumer substations has been studied
in several previous projects.
This paper addresses certain shortcomings inherent in
those previous works by presenting a novel
visualization approach using parallel coordinates and
scatter plot matrices. A comparison between these and
previous visualization techniques is presented and
discussed. Furthermore, the paper presents a scheme
for statistical analysis based on n-dimensional
relationships found in parallel coordinates and scatter
plot matrices, thus providing key performance
indicators appropriate for large-scale detection and
analysis. It is shown that the presented visualization
techniques are at least equal to previous attempts in
regards to fault detection and operational analysis,
while simultaneously addressing several of their
shortcomings. Furthermore, it is shown that the
subsequent statistical analysis provides a workable
starting point for system-wide fault detection and
analysis within any district heating system
Smart Heat Grid on an Intraday Power Market
No full textDistrict heating systems (DHS) is in many countries an important Agent-based
industrial applications, Smart Heat Grid, Combined part of the heating
infrastructure, especially in and around urban Heat and Power areas. Combined
heat and power (CHP) production makes it possible to producer heat while
simultaneously producing power.
This combination help maximize the energy efficiency in
production, often reaching an 80-90% utilization level of the
primary fuel, compared to around 30-50% in a traditional power plant. The heat
produced in the CHP plant is used to heat the adjacent DHS, while the power is
transferred and sold on the power market. The work presented in this paper
relates to the Nord Pool Spot power market, which is the leading power market
in Europe and one of the largest in the world. On Nord Pool Spot power is
bought and sold based on hourly spot prices, facilitated by the primary
day-ahead market and the supplementary balancing intraday market.
Since it isn’t possible to separate the physical process of
producing heat and power in a CHP production facility, the
energy company will want to synchronize high heat load
production with high spot prices for power whenever possible.
This can be done by using large storage tanks where heat is
buffered during hours with high spot prices, while then distributedto the DHS
as the heat load demand increases. However, such storage tanks are expensive to
build and maintain, and they have limited operational dynamics. An alternative
is to use the actual buildings connected to the DHS, in order to utilize their
thermal inertia by the use of active load control.
This paper presents a multi-agent system (MAS) designed to
bridge the information gap between energy companies and
building owners in order to enable the use of system-wide active load control
in order to synchronization heat load and spot prices.
The presented scheme provides a self-regulating market analogy in which agents
act to allocate load control resources. Each participating building is assigned
a consumer agent, while each production unit is represented by a production
agent. These agents interact on the market analogy which is in turn supervised
by a market agent. The work in this paper is focused on the intraday market
although the underpinning synchronization scheme is suitable for the day-ahead
market as well as the intraday market.
The results show considerable gains for participating entities
when applying the presented strategy to the often volatile intraday spot price
market
Similarity assessment for removal of noisy end user license agreements
No full textIn previous work, we have shown the possibility to automatically discriminate
between legitimate software and spyware-associated software by performing
supervised learning of end user license agreements (EULAs). However, the amount
of false positives (spyware classified as legitimate software) was too large
for practical use. In this study, the false positives problem is addressed by
removing noisy EULAs, which are identified by performing similarity analysis of
the previously studied EULAs. Two candidate similarity analysis methods for
this purpose are experimentally compared: cosine similarity assessment in
conjunction with latent semantic analysis (LSA) and normalized compression
distance (NCD). The results show that the number of false positives can be
reduced significantly by removing noise identified by either method. However,
the experimental results also indicate subtle performance differences between
LSA and NCD. To improve the performance even further and to decrease the large
number of attributes, the categorical proportional difference (CPD) feature
selection algorithm was applied. CPD managed to greatly reduce the number of
attributes while at the same time increase classification performance on the
original data set, as well as on the LSA- and NCD-based data sets
Outage Analysis of Cognitive Multihop Networks under Interference Constraints
No full textThe closed-form expressions for outage probability,
bit error rate, and ergodic capacity of spectrum sharing-based multi-hop
decode-and-forward relay networks in non-identical Rayleigh fading channels are
derived. Utilizing these precise and tractable analytical formulas, we can
study the impact of key network parameters on the performance of cognitive
multi-hop relay networks under interference constraints. The analytical
expressions are verified by Monte-Carlo simulations
Crowd Light: Evaluating the Perceived Fidelity of Illuminated Dynamic Scenes
No full textRendering realistic illumination effects for complex animated scenes with many
dynamic objects or characters is computationally expensive. Yet, it is not
obvious how important such accurate lighting is for the overall perceived
realism in these scenes. In this paper, we present a methodology to evaluate
the perceived fidelity of illumination in scenes with dynamic aggregates, such
as crowds, and explore several factors which may affect this perception. We
focus in particular on evaluating how a popular spherical harmonics lighting
method can be used to approximate realistic lighting of crowds. We conduct a
series of psychophysical experiments to explore how a simple approach to
approximating global illumination, using interpolation in the temporal domain,
affects the perceived fidelity of dynamic scenes with high geometric, motion,
and illumination complexity. We show that the complexity of the geometry and
temporal properties of the crowd entities, the motion of the aggregate as a
whole, the type of interpolation (i.e., of the direct and/or indirect
illumination coefficients), and the presence or absence of colour all affect
perceived fidelity. We show that high (i.e., above 75%) levels of perceived
scene fidelity can be maintained while interpolating indirect illumination for
intervals of up to 30 frames, resulting in a greater than three-fold rendering
speed-up