RISTCON 2018http://ir.lib.ruh.ac.lk/xmlui/handle/iruor/88212023-02-01T23:02:55Z2023-02-01T23:02:55ZQueueing a nalysis of p atients f low and o ptimal b ed r equirement of m aternity w ard in Matara h ospitalNivarthana, H.P.K.Jayasekara, L.A.L.W.http://ir.lib.ruh.ac.lk/xmlui/handle/iruor/106592023-02-01T10:29:17Z2018-02-15T00:00:00ZQueueing a nalysis of p atients f low and o ptimal b ed r equirement of m aternity w ard in Matara h ospital
Nivarthana, H.P.K.; Jayasekara, L.A.L.W.
The General hospital Matara is a major healthcare service provider in Matara district. There is some patients’ traffic in wards and some patients wait for days until they get a bed. Among these wards in the hospital maternity ward is always riddled with delays. This problem can be managed by using queueing model to determine the waiting line performance such as: arrival rate of expectant women, average service rate of expectant women and system utilization factor in the system.
This research surveys the contributions and applications of Queueing theory in the field of healthcare, examines data from maternity ward in Matara general hospital and uses Queueing analysis to estimate bed unavailability in maternity ward. The data were obtained for all patients in maternity ward over one-month period from July 01, 2016 to July 30, 2016. Queueing system is based on Single-Queue Multiple-Server model. Since arrivals follow a Poisson distribution, service time follows an exponential distribution and patients are served on first come first serve basis, M/M/s queuing model is used to find the optimal bed count. Results of the M/M/s queueing model were used to find the optimal bed requirement of the maternity ward.
2018-02-15T00:00:00ZComparative study on the buckling properties of Palmyra and Coconut treesHarsha Kumara, S.B.R.Kandasamy, K.http://ir.lib.ruh.ac.lk/xmlui/handle/iruor/106392023-02-01T09:27:57Z2018-02-15T00:00:00ZComparative study on the buckling properties of Palmyra and Coconut trees
Harsha Kumara, S.B.R.; Kandasamy, K.
In this study, a simple device was designed and developed
to to measure the
critical load to produce buckling of large wooden samples. Using this
device, the required critical load to produce buckling was analyzed for
Coconut and Palmyra trees. The actual load acting on the selected Coconut
trunk was measured as 1059.48 N and the estimated critical load is 1536.72
N . On the other hand, the critical load to bend the Palmyra trunk was
determined as 12734.10 N , while the actual load acting on that Palmyra
trunk was measured as just 2656.55 N . The ratio between the a ctual load
and critical load for bending in coconut tree is about 1:1.5 while the same
ratio is about 1:5 in Palmyra tree. The ratios from the study gives a reason
for this observed buckled shape of Coconut tree and Palmyra trees grown in
the nature. Furt her, the same device was used to measure the Young’s
modulus of the wooden trunks. The average values for the Young’s modulus
of the selected Coconut and Palmyra trunks were determined as 8.01×10 8 (±
2.47 x10 8 Nm 2 and 22.16×10 8 (± 3.90 x10 8 ) Nm 2 respect ively. Highest
young’s modulus and buckling coefficient of the Palmyra tree made it as the
most suitable material for construction work.
2018-02-15T00:00:00ZA simple and efficient incremental convex hull algorithm in 3D spaceWijeweera, K.R.Kodituwakku, S.R.http://ir.lib.ruh.ac.lk/xmlui/handle/iruor/106342023-02-01T09:12:40Z2018-02-15T00:00:00ZA simple and efficient incremental convex hull algorithm in 3D space
Wijeweera, K.R.; Kodituwakku, S.R.
The convex hull of a set S of points can be defined as the smallest convex
set containing all the points in S. The smallest convex set can be identified
as the smallest convex polyhedron in three dimensions. There are four
ex isting 3D convex hull algorithms: Naïve, Gift Wrapping, Divide &
Conquer, and Incremental with O (n 3 ), O (nF), O (n log n), and O (n 2 ) time
complexities respectively where n is the number of points and F is the
number of facets of the convex hull. The firs t three algorithms require the
entire set of points at the beginning to process. The incremental algorithm
can maintain the convex hull covering the points appearing one by one in
space. The existing incremental algorithm is very complicated due to the
use of advanced data structures for the implementation. The objective of
this work is to propose a new simpler algorithm. The convex hull is
represented by a set of triangular facets. If the new point appears inside the
existing convex hull then the point is ignored. If the new point appears
outside the existing convex hull then some set of facets should be removed
from the current convex hull and a new set of facets should be added. If
there are n points currently in the space, then there are kn facets in the
convex hull where k << n in the worst case. It takes O (kn) = O (n) time to
test whether the new point is outside each facet. In the worst case, the new
point is outside for ( kn 1) facets. Therefore, removing duplicate facets cost
O [{3(kn 1)} 2 ] = O n 2 ) time. Thus the proposed algorithm has O (n) + O
(n 2 ) = O (n 2 ) time complexity in the worst
2018-02-15T00:00:00ZBreeding preference of Aedes aegypti and Aedes albopictus (Diptera: Culicidae) in Galle District, Sri LankaDissanayake, D.M.D.S.Wegirya, H.C.E.http://ir.lib.ruh.ac.lk/xmlui/handle/iruor/106282023-02-01T08:57:45Z2018-02-15T00:00:00ZBreeding preference of Aedes aegypti and Aedes albopictus (Diptera: Culicidae) in Galle District, Sri Lanka
Dissanayake, D.M.D.S.; Wegirya, H.C.E.
Aedes aegypti and Aedes albopictus are main vectors of Dengue (DF) and Dengue Haemorrhagic (DHF) Fever in Sri Lanka. Both species are known to breed in microhabitats including water-filled containers, yet whether there is any breeding preference linked to features of containers/ microhabitats has not been addressed. Present study was conducted to find out breeding preference of the two Aedes species by estimating relative larval abundance in selected artificial and natural microhabitats. Nine larval surveys were conducted from January to October in 2017, and 1069 containers/ microhabitats were randomly sampled from three localities representing urban (n = 346), suburban (n = 367), and rural areas (n= 356) of Galle District. A total of 552 (51.63%) containers/ microhabitats were positive for both Ae. aegypti and Ae. albopictus larvae. Both species preferred artificial containers (90.57%) (including rubber tyres: 17.82%, plastic cups: 17.09%, and metal cups: 9.82%) than natural containers (9.43%) (including plant axils, coconut shells and wood caves). Analysis of percentage abundance of larvae revealed that both species had similar preference for black-coloured containers (47.98% for Ae. aegypti and 37.32 % for Ae. albopictus). Both species were abundant in containers having water level height less than 10 cm (Ae. aegypti 77.57% and Ae. albopictus70.11%) and containers with 50-100 ml of water (Ae. aegypti 29.28% and Ae. albopictus 41.79%). Their abundance increased with the presence of leaf litter in the containers (Ae. aegypti 80.69% and Ae. albopictus 73.77%). For both species, preferred water temperature was 31 ± 0.3oC (Ae. aegypti 58.23% and Ae. albopictus 61.21%) while preferred mean water pH was 7.44 ± 0.04 (Ae. aegypti 56.84% and Ae. albopictus 52.46%). Characteristic features such as the presence of leaf litter, pH and temperature of the logged water within the containers/ microhabitat may play an important role on the abundance of these two Aedes vector mosquito species.
2018-02-15T00:00:00Z