Search results for: figure and ground principle
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 3425

Search results for: figure and ground principle

3425 Tunnelling Concepts in Overstressed Weak Rocks

Authors: Entfellner Manuel, Wannenmacher Helmut, Reisenbauer Josef, Schubert Wulf

Abstract:

When tunnelling in overstressed weak rocks ("squeezing ground"), two basic design approaches are available: the resistance principle, and the yielding principle. The resistance principle relies on rigid support systems to withstand the ground pressure. Alternatively, the yielding principle prioritizes controlled deformation, allowing the ground to deform without compromising tunnel integrity. This paper highlights the beneficial factors of the yielding principle for conventionally excavated tunnels in overstressed weak rocks. Especially the application of a ductile shotcrete lining with yielding elements is analysed in detail. Construction costs, safety, short- and long-term stabilities are discussed.

Keywords: squeezing ground, yielding principle, yielding element, conventional tunneling

Procedia PDF Downloads 48
3424 Evidence-Based Investigation of the Phonology of Nigerian Instant Messaging

Authors: Emmanuel Uba, Lily Chimuanya, Maryam Tar

Abstract:

Orthographic engineering is no longer the preserve of the Short Messaging Service (SMS), which is characterised by limited space. Such stylistic creativity or deviation is fast creeping into real-time messaging, popularly known as Instant Messaging (IM), despite the large number of characters allowed. This occurs at various linguistic levels: phonology, morphology, syntax, etc. Nigerians are not immune to this linguistic stylisation. This study investigates the phonological and meta-phonological conventions of the messages sent and received via WhatsApp by Nigerian graduates. This is ontological study of 250 instant messages collected from 98 graduates from different ethnic groups in Nigeria. The selection and analysis of the messages are based on figure and ground principle. The results reveal the use of accent stylisation, phoneme substitution, blending, consonantisation (a specialised form of deletion targeting vowels), numerophony (using a figure/number, usually 1-10, to represent a word or syllable that has the same sound) and phonetic respelling in the IMs sent by Nigerians. The study confirms the existence of linguistic creativity.

Keywords: figure and ground principle, instant messaging, linguistic stylisation, meta-phonology

Procedia PDF Downloads 365
3423 Reduction of False Positives in Head-Shoulder Detection Based on Multi-Part Color Segmentation

Authors: Lae-Jeong Park

Abstract:

The paper presents a method that utilizes figure-ground color segmentation to extract effective global feature in terms of false positive reduction in the head-shoulder detection. Conventional detectors that rely on local features such as HOG due to real-time operation suffer from false positives. Color cue in an input image provides salient information on a global characteristic which is necessary to alleviate the false positives of the local feature based detectors. An effective approach that uses figure-ground color segmentation has been presented in an effort to reduce the false positives in object detection. In this paper, an extended version of the approach is presented that adopts separate multipart foregrounds instead of a single prior foreground and performs the figure-ground color segmentation with each of the foregrounds. The multipart foregrounds include the parts of the head-shoulder shape and additional auxiliary foregrounds being optimized by a search algorithm. A classifier is constructed with the feature that consists of a set of the multiple resulting segmentations. Experimental results show that the presented method can discriminate more false positive than the single prior shape-based classifier as well as detectors with the local features. The improvement is possible because the presented approach can reduce the false positives that have the same colors in the head and shoulder foregrounds.

Keywords: pedestrian detection, color segmentation, false positive, feature extraction

Procedia PDF Downloads 258
3422 Theoretical Investigation of Electronic, Structural and Thermoelectric Properties of Mg₂SiSn (110) Surface

Authors: M. Ramesh, Manish K. Niranjan

Abstract:

The electronic, structural and thermoelectric properties of Mg₂SiSn (110) surface are investigated within the framework of first principle density functional theory and semi classical Boltzmann approach. In particular, directional dependent thermoelectric properties such as electrical conductivity, thermal conductivity, Seebeck coefficient and figure of merit are explored. The (110)-oriented Mg₂SiSn surface exhibits narrow indirect band gap of ~0.17 eV. The thermoelectric properties are found to be significant along the y-axis at 300 K and along x-axis at 500 K. The figure of merit (ZT) for hole carrier concentration is found to be significantly large having magnitude 0.83 (along x-axis) at 500 K and 0.26 (y-axis) at 300 K. Our results suggest that Mg₂SiSn (110) surface is promising for various thermoelectric applications due to its overall good thermoelectric properties.

Keywords: thermoelectric, surface science, semiconducting silicide, first principles calculations

Procedia PDF Downloads 206
3421 Calculation of Lattice Constants and Band Gaps for Generalized Quasicrystals of InGaN Alloy: A First Principle Study

Authors: Rohin Sharma, Sumantu Chaulagain

Abstract:

This paper presents calculations of total energy of InGaN alloy carried out in a disordered quasirandom structure for a triclinic super cell. This structure replicates the disorder and composition effect in the alloy. First principle calculations within the density functional theory with the local density approximation approach is employed to accurately determine total energy of the system. Lattice constants and band gaps associated with the ground states are then estimated for different concentration ratios of the alloy. We provide precise results of quasirandom structures of the alloy and their lattice constants with the total energy and band gap energy of the system for the range of seven different composition ratios and their respective lattice parameters.

Keywords: DFT, ground state, LDA, quasicrystal, triclinic super cell

Procedia PDF Downloads 166
3420 Thermal Properties of the Ground in Cyprus and Their Correlations and Effect on the Efficiency of Ground Heat Exchangers

Authors: G. A. Florides, E. Theofanous, I. Iosif-Stylianou, P. Christodoulides, S. Kalogirou, V. Messarites, Z. Zomeni, E. Tsiolakis, P. D. Pouloupatis, G. P. Panayiotou

Abstract:

Ground Coupled Heat Pumps (GCHPs) exploit effectively the heat capacity of the ground, with the use of Ground Heat Exchangers (GHE). Depending on the mode of operation of the GCHPs, GHEs dissipate or absorb heat from the ground. For sizing the GHE the thermal properties of the ground need to be known. This paper gives information about the density, thermal conductivity, specific heat and thermal diffusivity of various lithologies encountered in Cyprus with various relations between these properties being examined through comparison and modeling. The results show that the most important correlation is the one encountered between thermal conductivity and thermal diffusivity with both properties showing similar response to the inlet and outlet flow temperature of vertical and horizontal heat exchangers.

Keywords: ground heat exchangers, ground thermal conductivity, ground thermal diffusivity, ground thermal properties

Procedia PDF Downloads 357
3419 A Case Study of the Ground Collapse Due to Excavation Using Non-Destructive Testing

Authors: Ki-Cheong Yoo, Yushik Han, Heejeung Sohn, Jinwoo Kim

Abstract:

A ground collapse can be caused by natural and artificial factors. Ground collapses that have occurred frequently in Korea were observed and classified into different types by the main contributing factor. In this study, ground collapse induced by groundwater level disturbance in an excavation site was analyzed. Also, ground loosening region around the excavation site was detected and analyzed using non-destructive testing, such as GPR (Ground Penetrating Radar) survey and Electrical Resistivity. The result of the surveys showed that the ground was loosened widely over the surrounding area of the excavation due to groundwater discharge.

Keywords: electrical resistivity, ground collapse, groundwater level, GPR (ground penetrating radar)

Procedia PDF Downloads 173
3418 Agegraphic Dark Energy with GUP

Authors: H. R. Fazlollahi

Abstract:

Dark Energy origin is unknown and so describing this mysterious component in large scale structure needs to manipulate our theories in general relativity. Although in most models, dark energy arises from extra terms through modifying Einstein-Hilbert action, maybe its origin traces back to fundamental aspects of ground energy of space-time given in quantum mechanics. Hence, diluting space-time in general relativity with quantum mechanics properties leads to the Karolyhazy relation corresponding energy density of quantum fluctuations of space-time. Through generalized uncertainty principle and an eye to Karolyhazy approach in this study we extend energy density of quantum fluctuations of space-time. Also, the application of this idea is considered in late time evolution and we have shown how extra term in generalized uncertainty principle plays as a plausible interaction term role in suggested model.

Keywords: generalized uncertainty principle, karolyhazy approach, agegraphic dark energy, cosmology

Procedia PDF Downloads 53
3417 Effects of Near-Fault Ground Motions on Earthquake-Induced Pounding Response of RC Buildings

Authors: Mehmet Akköse

Abstract:

In ground motions recorded in recent major earthquakes such as 1994 Northridge earthquake in US, 1995 Kobe earthquake in Japan, 1999 Chi-Chi earthquake in Taiwan, and 1999 Kocaeli earthquake in Turkey, it is noticed that they have large velocity pulses. The ground motions with the velocity pulses recorded in the vicinity of an earthquake fault are quite different from the usual far-fault earthquake ground motions. The velocity pulse duration in the near-fault ground motions is larger than 1.0 sec. In addition, the ratio of the peak ground velocity (PGV) to the peak ground acceleration (PGA) of the near-fault ground motions is larger than 0.1 sec. The ground motions having these characteristics expose the structure to high input energy in the beginning of the earthquake and cause large structural responses. Therefore, structural response to near-fault ground motions has received much attention in recent years. Interactions between neighboring, inadequately separated buildings have been repeatedly observed during earthquakes. This phenomenon often referred to as earthquake-induced structural pounding, may result in substantial damage or even total destruction of colliding structures during strong ground motions. This study focuses on effects of near-fault ground motions on earthquake-induced pounding response of RC buildings. The program SAP2000 is employed in the response calculations. The results obtained from the pounding analyses for near-fault and far-fault ground motions are compared with each other.

Keywords: near-fault ground motion, pounding analysis, RC buildings, SAP2000

Procedia PDF Downloads 239
3416 Sustainable Development: The Human Rights Approach to Environmental Protection in South Africa

Authors: CM van der Bank, Marjoné van der Bank

Abstract:

International and domestic environmental law has evolved quite rapidly in the last few decades. At the international level the Stockholm and Rio Declarations paved the way for a broad based consensus of the international community on environmental issues and principles. At the Domestic level also many states have incorporated environmental protection in their constitutions and even more states are doing the same at least in their domestic legislations. In this process of evolution environmental law has unleashed a number of novel principles such as; the participatory principle, the polluter pays principle, the precautionary principle, the inter-generational and intra-generational principles, the prevention principle, the sustainable development principle and so on.

Keywords: environment, human rights, international law, protection

Procedia PDF Downloads 449
3415 The Standard of Best Interest of the Child in Custody Adjudication under the Malaysian Laws

Authors: Roslina Che Soh

Abstract:

Best interest of the child has been the prevailing principle of the custody legislations of most nations in the world. The tremendous shift from parental rights to parental responsibilities throughout the centuries had made the principle of best interests of the child as the utmost matter which parents must uphold in child upbringing. Despite the commitment to this principle is significantly enshrined in the United Nation Convention on Rights of the Child, the content and application of the principle differs across borders. Differences persist notwithstanding many countries have experienced a substantial shift over the last several decades in the types of custodial arrangements that are thought to best serve children’s interests. The laws in Malaysia similarly uphold this principle but do not provide further deliberation on the principle itself. The principle is entirely developed by the courts through decided cases. Thus, this paper seeks to discuss the extent of the application of best interest of the child principle in custody disputes. In doing so, it attempts to provide an overview of the current laws and the approach of the Civil and the Shariah courts in Malaysia in applying the principle in determining custody disputes. For purposes of comparison, it briefly examines the legislations and the courts practices in Australia and England on this matter. The purpose is to determine the best standard to be adopted by Malaysia and to propose improvement to the laws whenever appropriate.

Keywords: child custody, best interest, Malaysian law, bioinformatics, biomedicine

Procedia PDF Downloads 257
3414 Thermoelectric Properties of Spark Plasma Sintered Te Doped Cu₃SbSe₄: Promising Thermoelectric Material

Authors: Kriti Tyagi, Bhasker Gahtori

Abstract:

Various groups have attempted on enhancing the thermoelectric figure-of-merit (ZT) of the Cu₃SbSe₄ compound by employing doping process. Efforts are made to study the thermoelectric performance of Cu₃SbSe₄ material doped with Te in different compositions (i. e. Cu₃Sb₁₋ₓTeₓSe₄, x = 0.005, 0.01, 0.015, 0.02). The different doping concentration has been selected to identify the suitable doping to increase the thermoelectric performance. Compared to pristine Cu₃SbSe₄, an enhancement of thermoelectric figure-of-merit was achieved for 0.005 Te doped Cu₃SbSe₄. This improvement can be attributed to the reduction of thermal conductivity for 0.005 Te doped Cu₃SbSe₄.

Keywords: figure-of-merit, polycrystalline, thermal conductivity, thermoelectric

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3413 Exploring the Physical Environment and Building Features in Earthquake Disaster Areas

Authors: Chang Hsueh-Sheng, Chen Tzu-Ling

Abstract:

Earthquake is an unpredictable natural disaster and intensive earthquakes have caused serious impacts on social-economic system, environmental and social resilience. Conventional ways to mitigate earthquake disaster are to enhance building codes and advance structural engineering measures. However, earthquake-induced ground damage such as liquefaction, land subsidence, landslide happen on places nearby earthquake prone or poor soil condition areas. Therefore, this study uses spatial statistical analysis to explore the spatial pattern of damaged buildings. Afterwards, principle components analysis (PCA) is applied to categorize the similar features in different kinds of clustered patterns. The results show that serious landslide prone area, close to fault, vegetated ground surface and mudslide prone area are common in those highly damaged buildings. In addition, the oldest building might not be directly referred to the most vulnerable one. In fact, it seems that buildings built between 1974 and 1989 become more fragile during the earthquake. The incorporation of both spatial statistical analyses and PCA can provide more accurate information to subsidize retrofit programs to enhance earthquake resistance in particular areas.

Keywords: earthquake disaster, spatial statistic analysis, principle components analysis (pca), clustered patterns

Procedia PDF Downloads 288
3412 Introducing the Accounting Reform of Public Finance in the Czech Republic

Authors: M. Otrusinova, E. Pastuszkova

Abstract:

The article is addressing the currently ongoing reform processes of transforming the public finance accounting based on cash flow principle to accrual principle. The presented analysis concerns the issues associated with the introduction of the state accounting from the perspective of municipal employees in compiling the opinions of financial experts in conditions of the Czech Republic. The aim of this paper is to present outcomes of analysis focused on currently discussed topics which are related to introducing the accrual principle into accounting of selected entities, especially municipalities and municipality-funded institutions. The output of the paper consists of comparing the application of the accrual principle in the financial reporting of municipalities in the Czech Republic and Slovakia. In conclusion and based on the survey, respondents from Slovak municipalities that have already adopted the accrual accounting principle show better opinion than Czech municipalities.

Keywords: accrual principle, accounting, accounting reform, Czech Republic, municipalities, public finance

Procedia PDF Downloads 238
3411 Preliminary Study on Analysis of Pinching Motion Actuated by Electro-Active Polymers

Authors: Doo W. Lee, Soo J. Lee, Bye R. Yoon, Jae Y. Jho, Kyehan Rhee

Abstract:

Hand exoskeletons have been developed in order to assist daily activities for disabled and elder people. A figure exoskeleton was developed using ionic polymer metal composite (IPMC) actuators, and the performance of it was evaluated in this study. In order to study dynamic performance of a finger dummy performing pinching motion, force generating characteristics of an IPMC actuator and pinching motion of a thumb and index finger dummy actuated by IMPC actuators were analyzed. The blocking force of 1.54 N was achieved under 4 V of DC. A thumb and index finger dummy, which has one degree of freedom at the proximal joint of each figure, was manufactured by a three dimensional rapid prototyping. Each figure was actuated by an IPMC actuator, and the maximum fingertip force was 1.18 N. Pinching motion of a dummy was analyzed by two video cameras in vertical top and horizontal left end view planes. A figure dummy powered by IPMC actuators could perform flexion and extension motion of an index figure and a thumb.

Keywords: finger exoskeleton, ionic polymer metal composite, flexion and extension, motion analysis

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3410 First Principle Calculations of Magnetic and Electronic Properties of Double Perovskite Ba2MnMoO6

Authors: B. Bouadjemi, S. Bentata, W. Benstaali, A. Souidi, A. Abbad, T. Lantri, Z. Aziz, A. Zitouni

Abstract:

The electronic and magnetic structures of double perovskite Ba2MnMoO6 are systematically investigated using the first principle method of the Full Potential Linear Augmented Plane Waves Plus the Local Orbitals (FP-LAPW+LO) within the Local Spin Density Approximation (LSDA) and the Generalized Gradient Approximation (GGA). In order to take into account the strong on-site Coulomb interaction, we included the Hubbard correlation terms: LSDA+U and GGA+U approaches. Whereas half-metallic ferromagnetic character is observed due to dominant Mn spin-up and Mo spin-down contributions insulating ground state is obtained. The LSDA+U and GGA+U calculations yield better agreement with the theoretical and the experimental results than LSDA and GGA do.

Keywords: electronic structure, double perovskite, first principles, Ba2MnMoO6, half-metallic

Procedia PDF Downloads 417
3409 Study on the Seismic Response of Slope under Pulse-Like Ground Motion

Authors: Peter Antwi Buah, Yingbin Zhang, Jianxian He, Chenlin Xiang, Delali Atsu Y. Bakah

Abstract:

Near-fault ground motions with velocity pulses are considered to cause significant damage to structures or slopes compared to ordinary ground motions without velocity pulses. The double pulsed pulse-like ground motion is as well known to be stronger than the single pulse. This study has numerically justified this perspective by studying the dynamic response of a homogeneous rock slope subjected to four pulse-like and two non-pulse-like ground motions using the Fast Lagrangian Analysis of Continua in 3 Dimensions (FLAC3D) software. Two of the pulse-like ground motions just have a single pulse. The results show that near-fault ground motions with velocity pulses can cause a higher dynamic response than regular ground motions. The amplification of the peak ground acceleration (PGA) in horizontal direction increases with the increase of the slope elevation. The seismic response of the slope under double pulse ground motion is stronger than that of the single pulse ground motion. The PGV amplification factor under the effect of the non-pulse-like records is also smaller than those under the pulse-like records. The velocity pulse strengthens the earthquake damage to the slope, which results in producing a more strong dynamic response.

Keywords: velocity pulses, dynamic response, PGV magnification effect, elevation effect, double pulse

Procedia PDF Downloads 135
3408 Monitoring and Analysis of Bridge Crossing Ground Fissures

Authors: Zhiqing Zhang, Xiangong Zhou, Zihan Zhou

Abstract:

Ground fissures can be seen in some cities all over the world. As a special urban geological disaster, ground fissures in Xi'an have caused great harm to infrastructure. Chang'an Road Interchange in Xi'an City is a bridge across ground fissures. The damage to Chang'an Road interchange is the most serious and typical. To study the influence of ground fissures on the bridge, we established a bridge monitoring system. The main monitoring items include elevation monitoring, structural displacement monitoring, etc. The monitoring results show that the typical failure is mainly reflected in the bridge deck damage caused by horizontal tension and vertical dislocation. For the construction of urban interchange spanning ground fissures, the interchange should be divided reasonably, a simple support structure with less restriction should be adopted, and the monitoring of supports should be strengthened to prevent the occurrence of beam falling.

Keywords: bridge monitoring, ground fissures, typical disease, structural displacement

Procedia PDF Downloads 190
3407 Methodology: A Review in Modelling and Predictability of Embankment in Soft Ground

Authors: Bhim Kumar Dahal

Abstract:

Transportation network development in the developing country is in rapid pace. The majority of the network belongs to railway and expressway which passes through diverse topography, landform and geological conditions despite the avoidance principle during route selection. Construction of such networks demand many low to high embankment which required improvement in the foundation soil. This paper is mainly focused on the various advanced ground improvement techniques used to improve the soft soil, modelling approach and its predictability for embankments construction. The ground improvement techniques can be broadly classified in to three groups i.e. densification group, drainage and consolidation group and reinforcement group which are discussed with some case studies.  Various methods were used in modelling of the embankments from simple 1-dimensional to complex 3-dimensional model using variety of constitutive models. However, the reliability of the predictions is not found systematically improved with the level of sophistication.  And sometimes the predictions are deviated more than 60% to the monitored value besides using same level of erudition. This deviation is found mainly due to the selection of constitutive model, assumptions made during different stages, deviation in the selection of model parameters and simplification during physical modelling of the ground condition. This deviation can be reduced by using optimization process, optimization tools and sensitivity analysis of the model parameters which will guide to select the appropriate model parameters.

Keywords: cement, improvement, physical properties, strength

Procedia PDF Downloads 156
3406 Studies on Race Car Aerodynamics at Wing in Ground Effect

Authors: Dharni Vasudhevan Venkatesan, K. E. Shanjay, H. Sujith Kumar, N. A. Abhilash, D. Aswin Ram, V. R. Sanal Kumar

Abstract:

Numerical studies on race car aerodynamics at wing in ground effect have been carried out using a steady 3d, double precision, pressure-based, and standard k-epsilon turbulence model. Through various parametric analytical studies we have observed that at a particular speed and ground clearance of the wings a favorable negative lift was found high at a particular angle of attack for all the physical models considered in this paper. The fact is that if the ground clearance height to chord length (h/c) is too small, the developing boundary layers from either side (the ground and the lower surface of the wing) can interact, leading to an altered variation of the aerodynamic characteristics at wing in ground effect. Therefore a suitable ground clearance must be predicted throughout the racing for a better performance of the race car, which obviously depends upon the coupled effects of the topography, wing orientation with respect to the ground, the incoming flow features and/or the race car speed. We have concluded that for the design of high performance and high speed race cars the adjustable wings capable to alter the ground clearance and the angles of attack is the best design option for any race car for racing safely with variable speeds.

Keywords: external aerodynamics, external flow choking, race car aerodynamics, wing in ground effect

Procedia PDF Downloads 334
3405 Translational and Rotational Effect of Earthquake Ground Motion on a Bridge Substructure

Authors: Tauhidur Rahman, Gitartha Kalita

Abstract:

In this study a four span box girder bridge is considered and effect of the rotational and translational earthquake ground motion have been thoroughly investigated. This study is motivated by the fact that in many countries the translational and rotational components of earthquake ground motion, especially rocking, is not adequately considered in analysing the overall response of the structures subjected to earthquake ground excitations. Much consideration is given to only the horizontal components of the earthquake ground motion during the response analysis of structures. In the present research work, P waves, SV waves and Rayleigh wave excitations are considered for different angle of incidence. In the present paper, the four span bridge is model considering the effects of vertical and rocking components of P, SV and Rayleigh wave excitations. Ground responses namely displacement, velocity and acceleration of the substructures of the bridge have been considered for rotational and translational effects in addition to the horizontal ground motion due to earthquake and wind.

Keywords: ground motion, response, rotational effects, translational effects

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3404 Ground State Phases in Two-Mode Quantum Rabi Models

Authors: Suren Chilingaryan

Abstract:

We study two models describing a single two-level system coupled to two boson field modes in either a parallel or orthogonal setup. Both models may be feasible for experimental realization through Raman adiabatic driving in cavity QED. We study their ground state configurations; that is, we find the quantum precursors of the corresponding semi-classical phase transitions. We found that the ground state configurations of both models present the same critical coupling as the quantum Rabi model. Around this critical coupling, the ground state goes from the so-called normal configuration with no excitation, the qubit in the ground state and the fields in the quantum vacuum state, to a ground state with excitations, the qubit in a superposition of ground and excited state, while the fields are not in the vacuum anymore, for the first model. The second model shows a more complex ground state configuration landscape where we find the normal configuration mentioned above, two single-mode configurations, where just one of the fields and the qubit are excited, and a dual-mode configuration, where both fields and the qubit are excited.

Keywords: quantum optics, quantum phase transition, cavity QED, circuit QED

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3403 Domestic and Foreign Terrorism: Evaluation of the Breeding Ground

Authors: T. K. Hung

Abstract:

Terrorism acts have occurred across both developed and developing states, with well-identified motivation and causes. For many years, terrorism eradication has become a major topic yet only passive actions were taken in response to acts. The linkage between the location of terrorism occurrence and breeding ground is not well-documented, resulting in the passive approach used in counter-terrorism nowadays. The evaluation investigates all post-9/11 terrorism affairs considering their state capacity, safety, ease of border access control, religion diversity, and technology access, to measure the level of breeding ground of the states. Those "weak" states with poor border access control, resources capacity and domestic safety are the best breeding ground for terrorists. Although many attacks were caused by religious motivation, religion diversity does not predict the breeding ground. States with censored technology access, particular computer-mediated communication, predict on the terrorism breeding ground, moderated by the level of breeding ground of neighboring states.

Keywords: counter-terrorism, lethality, security, terrorism

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3402 Comparison on Electrode and Ground Arrangements Effect on Heat Transfer under Electric Force in a Channel and a Cavity Flow

Authors: Suwimon Saneewong Na Ayuttaya, Chainarong Chaktranond, Phadungsak Rattanadecho

Abstract:

This study numerically investigates the effects of Electrohydrodynamic on flow patterns and heat transfer enhancement within a cavity which is on the lower wall of channel. In this simulation, effects of using ground wire and ground plate on the flow patterns are compared. Moreover, the positions of electrode wire respecting with ground are tested in the range of angles θ = 0 - 180°. High electrical voltage exposes to air is 20 kV. Bulk mean velocity and temperature of inlet air are controlled at 0.1 m/s and 60°C, respectively. The result shows when electric field is applied, swirling flow is appeared in the channel. In addition, swirling flow patterns in the main flow of using ground plate are widely spreader than that of using ground wire. Moreover, direction of swirling flow also affects the flow pattern and heat transfer in a cavity. These cause the using ground wire to give the maximum temperature and heat transfer higher than using ground plate. Furthermore, when the angle is at θ = 60°, high shear flow effect is obtained. This results show high strength of swirling flow and effective heat transfer enhancement.

Keywords: swirling flow, heat transfer, electrohydrodynamic, numerical analysis

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3401 Carbon Stock Estimation of Urban Forests in Selected Public Parks in Addis Ababa

Authors: Meseret Habtamu, Mekuria Argaw

Abstract:

Urban forests can help to improve the microclimate and air quality. Urban forests in Addis Ababa are important sinks for GHGs as the number of vehicles and the traffic constrain is steadily increasing. The objective of this study was to characterize the vegetation types in selected public parks and to estimate the carbon stock potential of urban forests by assessing carbon in the above, below ground biomass, in the litter and soil. Species which vegetation samples were taken using a systematic transect sampling within value DBH ≥ 5cm were recorded to measure the above, the below ground biomass and the amount of C stored. Allometric models (Y= 34.4703 - 8.0671(DBH) + 0.6589(DBH2) were used to calculate the above ground and Below ground biomass (BGB) = AGB × 0.2 and sampling of soil and litter was based on quadrates. There were 5038 trees recorded from the selected study sites with DBH ≥ 5cm. Most of the Parks had large number of indigenous species, but the numbers of exotic trees are much larger than the indigenous trees. The mean above ground and below ground biomass is 305.7 ± 168.3 and 61.1± 33.7 respectively and the mean carbon in the above ground and below ground biomass is 143.3±74.2 and 28.1 ± 14.4 respectively. The mean CO2 in the above ground and below ground biomass is 525.9 ± 272.2 and 103.1 ± 52.9 respectively. The mean carbon in dead litter and soil carbon were 10.5 ± 2.4 and 69.2t ha-1 respectively. Urban trees reduce atmospheric carbon dioxide (CO2) through sequestration which is important for climate change mitigation, they are also important for recreational, medicinal value and aesthetic and biodiversity conservation.

Keywords: biodiversity, carbon sequestration, climate change, urban forests

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3400 Max-Entropy Feed-Forward Clustering Neural Network

Authors: Xiaohan Bookman, Xiaoyan Zhu

Abstract:

The outputs of non-linear feed-forward neural network are positive, which could be treated as probability when they are normalized to one. If we take Entropy-Based Principle into consideration, the outputs for each sample could be represented as the distribution of this sample for different clusters. Entropy-Based Principle is the principle with which we could estimate the unknown distribution under some limited conditions. As this paper defines two processes in Feed-Forward Neural Network, our limited condition is the abstracted features of samples which are worked out in the abstraction process. And the final outputs are the probability distribution for different clusters in the clustering process. As Entropy-Based Principle is considered into the feed-forward neural network, a clustering method is born. We have conducted some experiments on six open UCI data sets, comparing with a few baselines and applied purity as the measurement. The results illustrate that our method outperforms all the other baselines that are most popular clustering methods.

Keywords: feed-forward neural network, clustering, max-entropy principle, probabilistic models

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3399 Numerical Simulation of the Flow around Wing-In-Ground Effect (WIG) Craft

Authors: A. Elbatran, Y. Ahmed, A. Radwan, M. Ishak

Abstract:

The use of WIG craft is representing an ambitious technology that will support in reducing time, effort, and money of the conventional marine transportation in the future. This paper investigates the aerodynamic characteristic of compound wing-in-ground effect (WIG) craft model. Drag coefficient, lift coefficient and Lift and drag ratio were studied numerically with respect to the ground clearance and the wing angle of attack. The modifications of the wing has been done in order to investigate the most suitable wing configuration that can increase the wing lift-to-drag ratio at low ground clearance. A numerical investigation was carried out in this research work using finite volume Reynolds-Averaged Navier-Stokes Equations (RANSE) code ANSYS CFX, Validation was carried out by using experiments. The experimental and the numerical results concluded that the lift to drag ratio decreased with the increasing of the ground clearance.

Keywords: drag Coefficient, ground clearance, navier-stokes, WIG

Procedia PDF Downloads 357
3398 Accurate Algorithm for Selecting Ground Motions Satisfying Code Criteria

Authors: S. J. Ha, S. J. Baik, T. O. Kim, S. W. Han

Abstract:

For computing the seismic responses of structures, current seismic design provisions permit response history analyses (RHA) that can be used without limitations in height, seismic design category, and building irregularity. In order to obtain accurate seismic responses using RHA, it is important to use adequate input ground motions. Current seismic design provisions provide criteria for selecting ground motions. In this study, the accurate and computationally efficient algorithm is proposed for accurately selecting ground motions that satisfy the requirements specified in current seismic design provisions. The accuracy of the proposed algorithm is verified using single-degree-of-freedom systems with various natural periods and yield strengths. This study shows that the mean seismic responses obtained from RHA with seven and ten ground motions selected using the proposed algorithm produce errors within 20% and 13%, respectively.

Keywords: algorithm, ground motion, response history analysis, selection

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3397 Development of Risk Management System for Urban Railroad Underground Structures and Surrounding Ground

Authors: Y. K. Park, B. K. Kim, J. W. Lee, S. J. Lee

Abstract:

To assess the risk of the underground structures and surrounding ground, we collect basic data by the engineering method of measurement, exploration and surveys and, derive the risk through proper analysis and each assessment for urban railroad underground structures and surrounding ground including station inflow. Basic data are obtained by the fiber-optic sensors, MEMS sensors, water quantity/quality sensors, tunnel scanner, ground penetrating radar, light weight deflectometer, and are evaluated if they are more than the proper value or not. Based on these data, we analyze the risk level of urban railroad underground structures and surrounding ground. And we develop the risk management system to manage efficiently these data and to support a convenient interface environment at input/output of data.

Keywords: urban railroad, underground structures, ground subsidence, station inflow, risk

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3396 Donoho-Stark’s and Hardy’s Uncertainty Principles for the Short-Time Quaternion Offset Linear Canonical Transform

Authors: Mohammad Younus Bhat

Abstract:

The quaternion offset linear canonical transform (QOLCT), which isa time-shifted and frequency-modulated version of the quaternion linear canonical transform (QLCT), provides a more general framework of most existing signal processing tools. For the generalized QOLCT, the classical Heisenberg’s and Lieb’s uncertainty principles have been studied recently. In this paper, we first define the short-time quaternion offset linear canonical transform (ST-QOLCT) and drive its relationship with the quaternion Fourier transform (QFT). The crux of the paper lies in the generalization of several well-known uncertainty principles for the ST-QOLCT, including Donoho-Stark’s uncertainty principle, Hardy’s uncertainty principle, Beurling’s uncertainty principle, and the logarithmic uncertainty principle.

Keywords: Quaternion Fourier transform, Quaternion offset linear canonical transform, short-time quaternion offset linear canonical transform, uncertainty principle

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