Abstract: Increasing our ability to solve complex engineering problems is directly related to the processing capacity of computers. By means of such equipments, one is able to fast and accurately run numerical algorithms. Besides the increasing interest in numerical simulations, probabilistic approaches are also of great importance. This way, statistical tools have shown their relevance to the modelling of practical engineering problems. In general, statistical approaches to such problems consider that the random variables involved follow a normal distribution. This assumption tends to provide incorrect results when skew data is present since normal distributions are symmetric about their means. Thus, in order to visualize and quantify this aspect, 9 statistical distributions (symmetric and skew) have been considered to model a hypothetical slope stability problem. The data modeled is the friction angle of a superficial soil in Brasilia, Brazil. Despite the apparent universality, the normal distribution did not qualify as the best fit. In the present effort, data obtained in consolidated-drained triaxial tests and saturated direct shear tests have been modeled and used to analytically derive the probability density function (PDF) of the safety factor of a hypothetical slope based on Mohr-Coulomb rupture criterion. Therefore, based on this analysis, it is possible to explicitly derive the failure probability considering the friction angle as a random variable. Furthermore, it is possible to compare the stability analysis when the friction angle is modelled as a Dagum distribution (distribution that presented the best fit to the histogram) and as a Normal distribution. This comparison leads to relevant differences when analyzed in light of the risk management.
Abstract: In subjective terms, Polish SME sector occupies a
prominent position in the national economic development, in which
planning of the management strategies should be primarily based on
identifying and meeting the innovation needs. As a research sample, there is chosen a printing sector of industry.
SMEs share in printing sector in Poland is estimated at the level of
81% of all enterprises. In recent years, the printing industry achieved
one of the highest levels of EU support in Poland. There is a
relatively high increase in the development of technological
innovations in equipment and the associated significant increase in
production capacity. It can be also noticed that on average, every
third enterprise belonging to the printing industry has implemented
innovations, but not all of them effected in better economic results.
Therefore, the aim of this article is to evaluate the impact of the
implementation of innovation projects financed from the EU funds
for performance of SMEs in the printing industry. As the results of research of EU funds co-financing effects on the
development of innovation in the printing industry, it was specified
that examined SMEs prefer to implement product innovation to
receive a grant to the project at a level between 40% to 60%, the
remaining part of the investment is usually covered with equity. The most common type of innovation had indicated a single
implementation, related only to the change in process, technology, or
organization. The relationship between variables of the EU funds and
management of innovative activities was verified. It has been
observed that the identified variables arising from the support in a
form of the EU funds had a positive effect on the level of earned
revenue, the increase in margin and in increase in employment as
well. It was confirmed that the implemented innovations supported
by the European funds have a positive impact on the performance of
the printing companies. Although there is a risk that due to the
decreasing demand for printing services such a high level of funding
the companies in this sector will significantly increase competition in
the long term, that may also contribute to the economic problems of
the enterprises belonging to the analyzed branch.
Abstract: Critical success factors (CSFs) and the criteria to measure project success have received much attention over the decades and are among the most widely researched topics in the context of project management. However, although there have been extensive studies on the subject by different researchers, to date, there has been little agreement on the CSFs. The aim of this study is to identify the CSFs that influence the performance of construction projects, and determine their relative importance for different objectives across five stages in the project life cycle. A considerable literature review was conducted that resulted in the identification of 179 individual factors. These factors were then grouped into nine major categories. A questionnaire survey was used to collect data from three groups of respondents: client representatives, consultants, and contractors. Out of 164 questionnaires distributed, 93 were returned, yielding a response rate of 56.7%. Using the mean score, relative importance index, and weighted average method, the top 10 critical factors for each category were identified. The agreement of survey respondents on those categorised factors were analysed using Spearman’s rank correlation. A one-way analysis of variance was then performed to determine whether the mean scores among the various groups of respondents were statistically significant. The findings indicate the most CSFs in each category in procurement phase are: proper procurement programming of materials (time), stability in the price of materials (cost), and determining quality in the construction (quality). They are then followed by safety equipment acquisition and maintenance (health and safety), budgeting allowed in a contractual arrangement for implementing environmental management activities (environment), completeness of drawing documents (productivity), accurate measurement and pricing of bill of quantities (risk management), adequate communication among the project team (human resource), and adequate cost control measures (client satisfaction). An understanding of CSFs would help all interested parties in the construction industry to improve project performance. Furthermore, the results of this study would help construction professionals and practitioners take proactive measures for effective project management.
Abstract: In general, it is desirable to finish the weld quickly,
before a large volume of surrounding metal heats up and expands.
The welding process used, type, welding current and speed of travel,
thus, affect the degree of shrinkage and distortion of a weldment. The
use of mechanized welding equipment reduces welding time, metal
affected zone and consequently distortion. This article helps to define
what weld distortion is and then provide a practical understanding of
the causes of distortion, effects of shrinkage in butt joint welded
assemblies using TI6AL4VA and Aluminium AA2024 alloy sheet.
The beam offset position to the joint interface towards titanium and
aluminium side. The factors affecting distortion during welding is
also given. Test results reveal that welding speed is the significant
parameter to decide the extent of distortion. Also welding from Al
side reduces the distortion while Ti side increases the distortion.
Abstract: The study was meant to identify the impediments to
female sports management and participation in the selected colleges.
Seven colleges of education in the south west parts of the country
were selected for the study. A total of one hundred and five subjects
were sampled to supply data. Only one hundred adequately
completed and returned, copies of the questionnaire were used for
data analysis. The collected data were analysed descriptively. The
result of the study showed that inadequate fund, personnel, facilities
equipment, supplies, management of sports, supervision and coaching
were some of the impediments to female sports management and
participation. Athletes were not encouraged to participate. Based on
the findings, it was recommended that the government should come
to the aid of the colleges by providing fund and other needs that will
make sports attractive for enhanced participation.
Abstract: The present paper examines the impact noise
transmission through some floor building assemblies. The Acoubat
software numerical simulation has been used to simulate the impact
noise transmission through different floor configurations used in
Algerian construction mode. The results are compared with the
available measurements. We have developed two experimental
methods, i) field method, and ii) laboratory method using Brüel and
Kjær equipments. The results show that the different cases of floor
configurations need some improvement to ensure the acoustic
comfort in the receiving apartment. The recommended value of the
impact sound level in the receiving room should not exceed 58 dB.
The important results obtained in this paper can be used as platform
to improve the Algerian building acoustic regulation aimed at the
construction of the multi-storey residential building.
Abstract: An analysis of the air tightness level is performed on a representative sample of school classrooms in Southern Spain, which allows knowing the infiltration level of these classrooms, mainly through its envelope, which can affect both energy demand and occupant's thermal comfort. By using a pressurization/depressurization equipment (Blower-Door test), a characterization of 45 multipurpose classrooms have been performed in nine non-university educational institutions of the main climate zones of Southern Spain. In spite of having two doors and a high ratio between glass surface and outer surface, it is possible to see in these classrooms that there is an adequate level of airtightness, since all the n50 values obtained are lower than 9.0 ACH, with an average value around 7.0 ACH.
Abstract: The paper focuses on the distance laboratory
organisation for training the electrical engineering staff and students
in the fields of electrical drive and power electronics. To support
online knowledge acquisition and professional enhancement, new
challenges in remote education based on an active learning approach
with self-assessment have been emerged by the authors. Following
the literature review and explanation of the improved assessment
methodology, the concept and technological basis of the labs
arrangement are presented. To decrease the gap between the distance
study of the up-to-date equipment and other educational activities in
electrical engineering, the improvements in the following-up the
learners’ progress and feedback composition are introduced. An
authoring methodology that helps to personalise knowledge
acquisition and enlarge Web-based possibilities is described.
Educational management based on self-assessment is discussed.
Abstract: Test automation allows performing difficult and time
consuming manual software testing tasks efficiently, quickly and
repeatedly. However, development and maintenance of automated
tests is expensive, so it needs a proper prioritization what to automate
first. This paper describes a simple yet efficient approach for such
prioritization of test cases based on the effort needed for both manual
execution and software test automation. The suggested approach is
very flexible because it allows working with a variety of assessment
methods, and adding or removing new candidates at any time. The
theoretical ideas presented in this article have been successfully
applied in real world situations in several software companies by the
authors and their colleagues including testing of real estate websites,
cryptographic and authentication solutions, OSGi-based middleware
framework that has been applied in various systems for smart homes,
connected cars, production plants, sensors, home appliances, car head
units and engine control units (ECU), vending machines, medical
devices, industry equipment and other devices that either contain or
are connected to an embedded service gateway.
Abstract: In this paper, we introduce a flexible box erecting
machine (BEM) that swiftly and automatically transforms cardboard
into a three dimensional box. Recently, the parcel service and
home-shopping industries have grown rapidly, and there is an
increasing need for various box types to ship various products.
However, workers cannot fold thousands of boxes manually in a day.
As such, automatic BEMs are garnering greater attention. This study
takes equipment operation into consideration as well as mechanical
improvements in order to design a BEM that is able to outperform its
conventional counterparts. We analyzed six dispatching rules – First In
First Out (FIFO), Shortest Processing Time (SPT), Earliest Due Date
(EDD), Setup Avoidance, EDD + SPT, and EDD + Setup Avoidance –
to determine which one was most suitable for BEM operation.
Consequently, SPT and Setup Avoidance were found to be the most
critical rules, followed by EDD + Setup Avoidance, EDD + SPT,
EDD, and FIFO. This hierarchy was valid for both our conventional
BEM and our new flexible BEM from the viewpoint of processing
time. We believe that this research can contribute to flexible BEM
management, which has the potential to increase productivity and
convenience.
Abstract: Production fluids are transported from the platform to
tankers or process facilities through transfer pipelines. Water being
one of the heavier phases tends to settle at the bottom of pipelines
especially at low flow velocities and this has adverse consequences
for pipeline integrity. On restart after a shutdown, this could result in
corrosion and issues for process equipment, thus the need to have the
heavier liquid dispersed into the flowing lighter fluid. This study
looked at the flow regime of low water cut and low flow velocity oil
and water flow using conductive film thickness probes in a large
diameter 4-inch pipe to obtain oil and water interface height and the
interface structural velocity. A wide range of 0.1–1.0 m/s oil and
water mixture velocities was investigated for 0.5–5% water cut. Two
fluid model predictions were used to compare with the experimental
results.
Abstract: The post-rain puddles problem that occurs in the first
yard of Prambanan Temple are often disturbing visitor activity. A
poodle layer and a drainage system had ever built to avoid such a
problem, but puddles still did not stop appearing after rain.
Permeability parameter needs to be determined by using a simpler
procedure to find exact method of solution. The instrument modelling
was proposed according to the development of field permeability
testing instrument. This experiment used a proposed Constant
Discharge method. Constant Discharge method used a tube poured
with constant water flow from unsaturated until saturated soil
condition. Volumetric water content (θ) were monitored by soil
moisture measurement device. The results were correlations between
k and θ which were drawn by numerical approach from Van
Genutchen model. Parameters θr optimum value obtained from the
test was at very dry soil. Coefficient of permeability with a density of
19.8 kN/m3 for unsaturated conditions was in range of 3 x 10-6
cm/sec (Sr=68%) until 9.98 x 10-4 cm/sec (Sr=82%). The equipment
and testing procedure developed in this research was quite effective,
simple and easy to be implemented on determining field soil
permeability coefficient value of sandy soil. Using constant discharge
method in proposed permeability test, value of permeability
coefficient under unsaturated condition can be obtained without
establish soil water characteristic curve.
Abstract: The paper discusses the problem of load transport
using farm tractors and road tractor units. This type of carriage of
goods is often done with farm vehicles. The tests were performed
with the PEMS equipment (Portable Emission Measurement System)
under actual traffic conditions. The vehicles carried a load of 20000
kg. This research method is one of the most desired because it
provides reliable information on the actual vehicle emissions and fuel
consumption (carbon balance method). For the tests, a route was
selected that simulated a trip from a small town to a food-processing
facility located in a city. The analysis of the obtained results gave a
clear answer as to what vehicles need to be used for carriage of this
type of cargo in terms of exhaust emissions and fuel consumption.
Abstract: The paper is focused to the evaluation railway tracks
in the Slovakia by using Multi-Criteria method. Evaluation of railway
tracks has important impacts for the assessment of investment in
technical equipment. Evaluation of railway tracks also has an
important impact for the allocation of marshalling yards. Marshalling
yards are in transport model as centers for the operation assigned
catchment area. This model is one of the effective ways to meet the
development strategy of the European Community's railways. By
applying this model in practice, a transport company can guarantee a
higher quality of service and then expect an increase in performance.
The model is also applicable to other rail networks. This model
supplements a theoretical problem of train formation problem of new
ways of looking at evaluation of factors affecting the organization of
wagon flows.
Abstract: This paper focuses on the orbit avoidance strategy of
the optical remote sensing satellite. The optical remote sensing
satellite, moving along the Sun-synchronous orbit, is equipped with
laser warning equipment to alert CCD camera from laser attacks. This
paper explores the strategy of satellite avoidance to protect the CCD
camera and also the satellite. The satellite could evasive to several
target points in the orbital coordinates of virtual satellite. The so-called
virtual satellite is a passive vehicle which superposes the satellite at the
initial stage of avoidance. The target points share the consistent cycle
time and the same semi-major axis with the virtual satellite, which
ensures the properties of the satellite’s Sun-synchronous orbit remain
unchanged. Moreover, to further strengthen the avoidance capability
of satellite, it can perform multi-target-points avoid maneuvers. On
occasions of fulfilling the satellite orbit tasks, the orbit can be restored
back to virtual satellite through orbit maneuvers. There into, the avoid
maneuvers adopts pulse guidance. In addition, the fuel consumption is
optimized. The avoidance strategy discussed in this article is
applicable to optical remote sensing satellite when it is encountered
with hostile attack of space-based laser anti-satellite.
Abstract: Temperature regulating system by gaseous nitrogen is
of importance to the space environment simulator, which keeps the
shrouds in the temperature range from -150°C to +150°C. Liquid
nitrogen spray equipment is one of the most critical parts in the
temperature regulating system by gaseous nitrogen. Y type jet
atomizer and internal mixing atomizer of the liquid nitrogen spray
equipment are studied in this paper, 2D/3D atomizer model was
established and grid division was conducted respectively by the
software of Catia and ICEM. Based on the above preparation,
numerical simulation on the spraying process of the atomizer by
FLUENT is performed. Using air and water as the medium,
comparison between the tests and numerical simulation was conducted
and the results of two ways match well. Hence, it can be conclude that
this atomizer model can be applied in the numerical simulation of
liquid nitrogen spray equipment.
Abstract: The aim of optimization of store management is not
only designing the situation of store management itself including its
equipment, technology and operation. In optimization of store
management we need to consider also synchronizing of
technological, transport, store and service operations throughout the
whole process of logistic chain in such a way that a natural flow of
material from provider to consumer will be achieved the shortest
possible way, in the shortest possible time in requested quality and
quantity and with minimum costs. The paper deals with the
application of the queuing theory for optimization of warehouse
processes. The first part refers to common information about the
problematic of warehousing and using mathematical methods for
logistics chains optimization. The second part refers to preparing a
model of a warehouse within queuing theory. The conclusion of the
paper includes two examples of using queuing theory in praxis.
Abstract: This study presents a kinematic positioning approach
that uses a global positioning system (GPS) buoy for precise ocean
surface monitoring. The GPS buoy data from the two experiments are
processed using an accurate, medium-range differential kinematic
technique. In each case, the data from a nearby coastal site are
collected at a high rate (1 Hz) for more than 24 hours, and
measurements are conducted in neighboring tidal stations to verify
the estimated sea surface heights. The GPS buoy kinematic
coordinates are estimated using epoch-wise pre-elimination and a
backward substitution algorithm. Test results show that centimeterlevel
accuracy can be successfully achieved in determining sea
surface height using the proposed technique. The centimeter-level
agreement between the two methods also suggests the possibility of
using this inexpensive and more flexible GPS buoy equipment to
enhance (or even replace) current tidal gauge stations.
Abstract: Students of Higher Education Technical School of
Professional Studies in Novi Sad follow the subject ‘Maintenance of
Electric Power Equipment’ at the Electrotechnical Department. This
paper presents educational plan and program of the subject
Maintenance of Electric Power Equipment. The course deals with the
problems of preventive and investing maintenance of transformer
stations (TS), performing and maintenance of grounding of TS and
pillars, as well as tracing and detection the location of the cables
failure. There is a special elaborated subject concerning the safe work
conditions for the electrician during network maintenance, as well as
the basics of making and keeping technical documentation of the
equipment.
Abstract: The shielding ability of a shielding cavity with an
aperture will be greatly degraded at resonance frequencies, and the
resonance modes and frequencies are affected by aperture resonances
and aperture-cavity coupling, which are closely related with aperture
sizes. The equivalent circuit method and numerical method of
Transmission Line Matrix (TLM) are used to analyze the effects of
aperture resonances and aperture-cavity coupling on the
electromagnetic resonances of a cavity with an aperture in this paper.
Both analytical and numerical results show that the resonance modes
of a shielding cavity with an aperture consist of cavity resonance
modes and aperture resonance modes, and the resonance frequencies
will shift with the change of the aperture sizes because of the aperture
resonances and aperture-cavity coupling. Variation rules of
electromagnetic resonances with aperture sizes for a cavity with an
aperture are given, which will be useful for design of shielding
cavities.