UET Peshawar Publications Site (University of Engineering and Technology, Peshawar)
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SURVIVAL TREES - A TRANSITION APPROACH
No full textThe traditional CART procedure1 of simply stating the number of subjects belonging to each node of a tree is inadequate in the context of survival data. This methodology has been extended by Segal2 to accommodate right censoring, and further extended by Bacchetti and Segal3 to allow for time-de pendent covariates, and to handle a complex situation of variable membership by introducing “pseudo- subjects“.In this paper we present a tree-based method focusing on transitions rather than subjects, to make the procedure simpler and more applicable. A new labeling scheme for the nodes of a tree is introduced in order to facilitate the implementation of the proposed method. The standard Kaplan-Meier method4 is modified to handle the situation where different type of transitions occur at different time points. Computer implementation is greatly facilitated by use of the dynamic transition approach and binary-labeling scheme
WATER MOVEMENT THROUGH SOIL IN RESPONSE TO MATRIC-POTENTIAL AND TEMPERATURE GRADIENTS: I. THEORETICAL DEVELOPMENTS
No full textThe theory of Philip and de Vries' has been used extensively to describe water movement in response to water-content and temperature gradients. Their theory is applicable for homogeneous and salt free soils. The same theory is recast in terms of matric-potential and temperature gradients to make it applicable in saline and heterogeneous soils. The theory is also extended to allow for the effects of temperature and osmotic potential on relative humidity. Thermal vapour diffusivity, with and without the temperature dependence of relative humidity, is discussed. It is concluded that the effect of temperature on relative humidity may be ignored in the temperature range (20-50 C°), generally encountered in agricultural soils. The isothermal vapour conductivity due to matric-potential gradient in extremely small except at very low water contents and the isothermal vapour conductivity due to osmotic-potential gradient (Kvo) is the smallest among the vapour conductivies. Salt concentration has negligibleeffects on Kvo
IMPACT OF pH AND CONCENTRATION ON THE REMOVAL OF MAGNESIUM FROM MAGNESIUM CHLORIDE SOLUTION BY CHINA CLAY
No full textThe effect of pH and concentration on the removal of magnesium from magnesium chloride solution by China clay (Kaolinite) has been studied. Adsorption equilibrium was found to be established within two hours in case of magnesium chloride solution of 50 and 100 mg/L concentration.Freundlich's and Langmuir's equations were applied to the isotherms data and found to be obeyed very well
SPLITTING AND STOPPING RULE: A TREE-GROWING PROCEDURE
No full textDue to limited,computer time, it is not feasible to grow a large tree in the first place and prune it back, especially in the study involving time dependent covariate.
The splitting and stopping rule advocated in this paper is similar to ” repairing " introduced by Zhang, et al' A semi-automatic three-way tree growing procedure will allow room for the analyst to make use of his knowledge of the date.
The approach is based on the utilization of available information from the raw data to implement forward stopping rule to avoid growing a large tree.
The value of the employed test statistic, adjusted sample size(2), and scientific knowledge of the data are used for the decision of stopping or splitting.
To grow two or more than two trees for different treatment groups, the same procedure can be employed with little alteration to the use of employed test statistic
DETERMINATION OF THE RELATION BETWEEN COMPRESSIVE STRENGTHS OF ASPHALT CONCRETE OBTAINED FROM HVEEM STABILOMETER AND UNCONFINED COMPRESSION TESTS
No full textUnconfined compression test is one of the common experiments to determine the compressive strength of asphalt concrete mixtures. In this test, the asphalt concrete sample is loaded under vertical pressure (oj) and the lateral pressure on the sample (cj) during the loading procedure is zero. It is obvious that this results in a reduction in the compressive strength of the asphalt concrete.In the present investigation, by making asphalt concrete samples with different specifications, the compressive strength values were determined through unconfined compression test and the results were analysed by comparing them with those obtained from Hveem stabilometer test on the same samples. The effect of the elemination of lateral pressure (Os) was clarified and finally, a mathematical model was presented to determine the relation between the compressive strengths obtained from these two tests
ACTUATION ENHANCEMENT OF A MICRO BIMORPH THERMAL ACTUATOR
No full textA bimorph thermal actuator (BTA) is typically used to actuate other MEMS structures, such as, micro-mirrors, atomic force microscope probe tips, membranes of micro pumps and micro valves, etc. This research is focused on enhancing BTA actuation characteristics. The mathematical model for BTA is used to study the behaviour of a spectrum of material combinations. Although a silicon-aluminum (SiO2-Al) BTA exhibits superior characteristics over a limited operational range, it is found that a silicon-stainless steel (Si-SS) bimorph provides larger deflections at higher operational conditions. The practical constraints on traditional bimorph materials in extreme operating conditions arise from intrinsic material properties such as yield strength and melting temperature. Under such extreme conditions Si-SS bimorphs perform well, opening up new field applications for this micro device. In order to fabricate the novel Si-Steel bimorph, a generic fabrication sequence is described according to criteria of reproducibility, batch fabrication, applicability and cost effectiveness with the use of newer micro fabrication techniques such Pulsed Laser Deposition (PLD), Laser Ablation (LA) and Micro electro-discharge machining (μEDM). Different designs of bimorph thermally actuated digital micro-mirror devices (DMDs) are also fabricated by the same generic fabrication process in order to show the practical utility of this research in the field of MEMS. The DMDs actuated by BTAs, are easy to fabricate and can scan through larger angles as compared to electrostatically actuated DMDs
A SURVEY OF MOBILE PHONES CONTEXT-AWARENESS USING SENSING COMPUTING RESEARCH
No full text
Recent technological advancements have not only emerged mobile phones as the key computing and communication platforms for performing individual's daily activities but have turned them into global sensing devices as well. Mobile phones sensing is a novel mobile phones context-aware computing paradigm enabling mobile phones to discover and capture peoples' contextual information, paving the way for the development of cutting-edge context-aware applications. Mobile phone sensing is old wine in a new bottle, having its roots extended from context-aware mobile computing. Mobile phones sensing capabilities can be exploited for developing context-aware applications to answer a number of real-world problems belonging to different sectors including automatic road condition detection and traffic monitoring, social networking, environmental pollution monitoring, and healthcare monitoring etc. This paper presents a comprehensive survey of research efforts contributed by researchers, organizations, and academia emphasizing on using mobile phones sensing capabilities for developing effective context-aware applications. The readily available knowledge is organized and classified effectively to give insight knowledge about the phenomena. We believe that this paper will serve as a compact platform for researchers and learners to shine their understandings and address the open issues and challenges which exist or can emerge in this novel paradigm. A number of research dimensions are also highlighted to help researchers in finding research topics
CONTINGENCY ANALYSIS OF WAPDA'S 500/220 kV PRIMARY TRANSMISSION SYSTEM USING BUS IMPEDANCE MATRIX (Zbus)
No full textThis paper is based on a linear contingency analysis program that computes line flow changes and bus voltage changes resulting from branch outages and generation changes. A modern formulation has been adopted based on the relation V=IZ. For maximum speed in processing large number of contingencies, line (branch) outage distribution factors are computed and stored through separate small program. Besides retrieval of these factors and reading of relevant data, the main program is also capable of calculating these factors using elements of bus impedance matrix (Zbus) and branch impedances. The computer language used for contingency analysis program is BASIC 5.1 codeable on Hewlett Packard computer. The language is very fast, comprehensive and powerful to code scientific programmable instructions and is combination of FORTRAN-77, PASCAL and BASIC P.C. based language. The resulting program processes single to four branch outages at a time for 50 buses WAPDA 'S 500/220 kV primary transmission system for 119 branches along with generation changes at 17 buses for 102 generating units in about 1.89 seconds on a Hewlett Packard Management Computer. 1.2.
FUNDAMENTAL STRENGTH PROPERTIES AND MATERIAL CONSTANTS OF CONCRETE WITH MACHINE SHOP SCRAP AS FIBRE REINFORCEMENT
No full textIn continuation with earlier experimental study in respect of suitability of Machine shop scrap as fibre reinforcement for micro-concrete and the consequent improvement achieved, this experimental study has been carried out todetermine the impact of this particular material on the properties of normal ordinary concrete with coarse aggregate. The study includes the determination of two strength properties, compressive strength and tensile strength and two material constants i.e. modulus of elasticity and Poisson's ratio. Here the main variable is the ratio of steel scrap chip fragments ranging between 0% to 2% with an increment of 0.5%. Ordinary concrete of grade 30 was selected as mass concrete and was kept constant for all the specimen. The results are encouraging and a substantial improvement in almost all the properties has been recorde
HIGH RISE BUILDINGS AND THEIR SOCIO-ENVIRONMENTAL PROBLEMS: A CASE STUDY OF HYDERABAD
No full textThis paper is aimed to share the socio-environmental problems faced by the residents of the high rise buildings in Hyderabad, the 5th most populous city of Pakistan, through a “ public opinion survey” . Alarming populationgrowth rate in the country, rural-to-urban migration in search of better opportunities, limited availability of land in old towns and cities and limited financial resources of the occupants have encouraged the builders and even thegovernment functionaries to address the housing problem with the construction of high rise buildings in urban centers. Though two studies of this nature, including one by the principal author, have been conducted in Karachi butno such information is available in the case of Hyderabad city. This study was conducted in May 2002 and the authors are aware that still more comprehensive work is needed.From the survey it is worked out that despite a number of problems faced by the residents, they do prefer to live in the high rise building apartments due to poor condition of rented houses, unplanned urban growth, and lackof facilities in suburbs. This is different as observed in Karachi where people wish to live in a house. 75% feel that high rise buildings have increased the traffic congestion and subsequent air and noise pollution in their area, andtheir privacy is greatly affected