11,853 research outputs found
Development of bent-up triangular tab shear transfer (BTTST) enhancement in cold-formed steel (CFS)-concrete composite beams
Cold-formed steel (CFS) sections, have been recognised as an important
contributor to environmentally responsible and sustainable structures in developed
countries, and CFS framing is considered as a sustainable 'green' construction material
for low rise residential and commercial buildings. However, there is still lacking of data
and information on the behaviour and performance of CFS beam in composite
construction. The use of CFS has been limited to structural roof trusses and a host of nonstructural applications. One of the limiting features of CFS is the thinness of its section
(usually between 1.2 and 3.2 mm thick) that makes it susceptible to torsional,
distortional, lateral-torsional, lateral-distortional and local buckling. Hence, a reasonable
solution is resorting to a composite construction of structural CFS section and reinforced
concrete deck slab, which minimises the distance from the neutral-axis to the top of the
deck and reduces the compressive bending stress in the CFS sections. Also, by arranging
two CFS channel sections back-to-back restores symmetricity and suppresses lateraltorsional and to a lesser extent, lateral-distortional buckling. The two-fold advantages
promised by the system, promote the use of CFS sections in a wider range of structural
applications. An efficient and innovative floor system of built-up CFS sections acting
compositely with a concrete deck slab was developed to provide an alternative composite
system for floors and roofs in buildings. The system, called Precast Cold-Formed SteelConcrete Composite System, is designed to rely on composite actions between the CFS
sections and a reinforced concrete deck where shear forces between them are effectively
transmitted via another innovative shear transfer enhancement mechanism called a bentup triangular tab shear transfer (BTTST). The study mainly comprises two major
components, i.e. experimental and theoretical work. Experimental work involved smallscale and large-scale testing of laboratory tests. Sixty eight push-out test specimens and
fifteen large-scale CFS-concrete composite beams specimens were tested in this program.
In the small-scale test, a push-out test was carried out to determine the strength and
behaviour of the shear transfer enhancement between the CFS and concrete. Four major
parameters were studied, which include compressive strength of concrete, CFS strength,
dimensions (size and angle) of BTTST and CFS thickness. The results from push-out test
were used to develop an expression in order to predict the shear capacity of innovative
shear transfer enhancement mechanism, BTTST in CFS-concrete composite beams. The
value of shear capacity was used to calculate the theoretical moment capacity of CFSconcrete composite beams. The theoretical moment capacities were used to validate the
large-scale test results. The large-scale test specimens were tested by using four-point
load bending test. The results in push-out tests show that specimens employed with
BTTST achieved higher shear capacities compared to those that rely only on a natural
bond between cold-formed steel and concrete and specimens with Lakkavalli and Liu
bent-up tab (LYLB). Load capacities for push-out test specimens with BTTST are
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relatively higher as compared to the equivalent control specimen, i.e. by 91% to 135%.
When compared to LYLB specimens the increment is 12% to 16%. In addition, shear
capacities of BTTST also increase with the increase in dimensions (size and angle) of
BTTST, thickness of CFS and concrete compressive strength. An equation was
developed to determine the shear capacity of BTTST and the value is in good agreement
with the observed test values. The average absolute difference between the test values
and predicted values was found to be 8.07%. The average arithmetic mean of the
test/predicted ratio (n) of this equation is 0.9954. The standard deviation (a) and the
coefficient of variation (CV) for the proposed equation were 0.09682 and 9.7%,
respectively. The proposed equation is recommended for the design of BTTST in CFSconcrete composite beams. In large-scale testing, specimens employed with BTTST
increased the strength capacities and reduced the deflection of the specimens. The
moment capacities, MU ) e X p for all specimens are above Mu>theory and show good agreement
with the calculated ratio (>1.00). It is also found that, strength capacities of CFS-concrete
composite beams also increase with the increase in dimensions (size and angle) of
BTTST, thickness of CFS and concrete compressive strength and a CFS-concrete
composite beam are practically designed with partial shear connection for equal moment
capacity by reducing number of BTTST. It is concluded that the proposed BTTST shear
transfer enhancement in CFS-concrete composite beams has sufficient strength and is
also feasible. Finally, a standard table of characteristic resistance, P t a b of BTTST in
normal weight concrete, was also developed to simplify the design calculation of CFSconcrete composite beams
Fusion of aerial images and sensor data from a ground vehicle for improved semantic mapping
This work investigates the use of semantic information to link ground level occupancy maps and aerial images. A ground level semantic map, which shows open ground and indicates the probability of cells being occupied by walls of buildings, is obtained by a mobile robot equipped with an omnidirectional camera, GPS and a laser range finder. This semantic information is used for local and global segmentation of an aerial image. The result is a map where the semantic information has been extended beyond the range of the robot sensors and predicts where the mobile robot can find buildings and potentially driveable ground
Viewfinder: final activity report
The VIEW-FINDER project (2006-2009) is an 'Advanced Robotics' project that seeks to apply a semi-autonomous robotic system to inspect ground safety in the event of a fire. Its primary aim is to gather data (visual and chemical) in order to assist rescue personnel. A base station combines the gathered information with information retrieved from off-site sources.
The project addresses key issues related to map building and reconstruction, interfacing local command information with external sources, human-robot interfaces and semi-autonomous robot navigation.
The VIEW-FINDER system is a semi-autonomous; the individual robot-sensors operate autonomously within the limits of the task assigned to them, that is, they will autonomously navigate through and inspect an area. Human operators monitor their operations and send high level task requests as well as low level commands through the interface to any nodes in the entire system. The human interface has to ensure the human supervisor and human interveners are provided a reduced but good and relevant overview of the ground and the robots and human rescue workers therein
Radar and RGB-depth sensors for fall detection: a review
This paper reviews recent works in the literature on the use of systems based on radar and RGB-Depth (RGB-D) sensors for fall detection, and discusses outstanding research challenges and trends related to this research field. Systems to detect reliably fall events and promptly alert carers and first responders have gained significant interest in the past few years in order to address the societal issue of an increasing number of elderly people living alone, with the associated risk of them falling and the consequences in terms of health treatments, reduced well-being, and costs. The interest in radar and RGB-D sensors is related to their capability to enable contactless and non-intrusive monitoring, which is an advantage for practical deployment and users’ acceptance and compliance, compared with other sensor technologies, such as video-cameras, or wearables. Furthermore, the possibility of combining and fusing information from The heterogeneous types of sensors is expected to improve the overall performance of practical fall detection systems. Researchers from different fields can benefit from multidisciplinary knowledge and awareness of the latest developments in radar and RGB-D sensors that this paper is discussing
Tahap penguasaan, sikap dan minat pelajar Kolej Kemahiran Tinggi MARA terhadap mata pelajaran Bahasa Inggeris
Kajian ini dilakukan untuk mengenal pasti tahap penguasaan, sikap dan minat pelajar
Kolej Kemahiran Tinggi Mara Sri Gading terhadap Bahasa Inggeris. Kajian yang
dijalankan ini berbentuk deskriptif atau lebih dikenali sebagai kaedah tinjauan. Seramai
325 orang pelajar Diploma in Construction Technology dari Kolej Kemahiran Tinggi
Mara di daerah Batu Pahat telah dipilih sebagai sampel dalam kajian ini. Data yang
diperoleh melalui instrument soal selidik telah dianalisis untuk mendapatkan
pengukuran min, sisihan piawai, dan Pekali Korelasi Pearson untuk melihat hubungan
hasil dapatan data. Manakala, frekuensi dan peratusan digunakan bagi mengukur
penguasaan pelajar. Hasil dapatan kajian menunjukkan bahawa tahap penguasaan
Bahasa Inggeris pelajar adalah berada pada tahap sederhana manakala faktor utama yang
mempengaruhi penguasaan Bahasa Inggeris tersebut adalah minat diikuti oleh sikap.
Hasil dapatan menggunakan pekali Korelasi Pearson juga menunjukkan bahawa terdapat
hubungan yang signifikan antara sikap dengan penguasaan Bahasa Inggeris dan antara
minat dengan penguasaan Bahasa Inggeris. Kajian menunjukkan bahawa semakin positif
sikap dan minat pelajar terhadap pengajaran dan pembelajaran Bahasa Inggeris semakin
tinggi pencapaian mereka. Hasil daripada kajian ini diharapkan dapat membantu pelajar
dalam meningkatkan penguasaan Bahasa Inggeris dengan memupuk sikap positif dalam
diri serta meningkatkan minat mereka terhadap Bahasa Inggeris dengan lebih baik. Oleh
itu, diharap kajian ini dapat memberi panduan kepada pihak-pihak yang terlibat dalam
membuat kajian yang akan datang
3D environment mapping using the Kinect V2 and path planning based on RRT algorithms
This paper describes a 3D path planning system that is able to provide a solution trajectory for the automatic control of a robot. The proposed system uses a point cloud obtained from the robot workspace, with a Kinect V2 sensor to identify the interest regions and the obstacles of the environment. Our proposal includes a collision-free path planner based on the Rapidly-exploring Random Trees variant (RRT*), for a safe and optimal navigation of robots in 3D spaces. Results on RGB-D segmentation and recognition, point cloud processing, and comparisons between different RRT* algorithms, are presented.Peer ReviewedPostprint (published version
Novel point-to-point scan matching algorithm based on cross-correlation
The localization of mobile robots in outdoor and indoor environments is a complex issue. Many sophisticated approaches, based
on various types of sensory inputs and different computational concepts, are used to accomplish this task. However, many of the
most efficient methods for mobile robot localization suffer from high computational costs and/or the need for high resolution
sensory inputs. Scan cross-correlation is a traditional approach that can be, in special cases, used to match temporally aligned scans
of robot environment. This work proposes a set of novel modifications to the cross-correlation method that extend its capability
beyond these special cases to general scan matching and mitigate its computational costs so that it is usable in practical settings.
The properties and validity of the proposed approach are in this study illustrated on a number of computational experiments.Web of Scienceart. ID 646394
Roving vehicle motion control Quarterly report, 1 Mar. - 31 May 1967
System and subsystem requirements for remote control of roving space vehicle motio
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