3,115 research outputs found
Motorized cart
Motorized cart is known as an effective tool and timeless that help people carry heavy loads. For farmers, it has an especially vital tool for moving goods. Oil palm farmers typically uses the wheelbarrow to move the oil palm fruit (Figure 10.1). However, there is a lack of equipment that should be further enhanced in capabilities. Motorized carts that seek to add automation to wheelbarrow as it is to help people save manpower while using it. At present, oil palm plantation industry is among the largest in Malaysia. However, in an effort to increase the prestige of the industry to a higher level there are challenges to be faced. Shortage of workers willing to work the farm for harvesting oil palm has given pain to manage oil palm plantations. Many have complained about the difficulty of hiring foreign workers and a high cost. Although there are tools that can be used to collect or transfer the proceeds of oil palm fruits such as carts available. However, these tools still have the disadvantage that requires high manpower to operate. Moreover, it is not suitable for all land surfaces and limited cargo space. Workload and manpower dependence has an impact on farmers' income
EVM as generic QoS trigger for heterogeneous wieless overlay network
Fourth Generation (4G) Wireless System will integrate heterogeneous wireless
overlay systems i.e. interworking of WLAN/ GSM/ CDMA/ WiMAX/ LTE/ etc with
guaranteed Quality of Service (QoS) and Experience (QoE).QoS(E) vary from
network to network and is application sensitive. User needs an optimal mobility
solution while roaming in Overlaid wireless environment i.e. user could
seamlessly transfer his session/ call to a best available network bearing
guaranteed Quality of Experience. And If this Seamless transfer of session is
executed between two networks having different access standards then it is
called Vertical Handover (VHO). Contemporary VHO decision algorithms are based
on generic QoS metrics viz. SNR, bandwidth, jitter, BER and delay. In this
paper, Error Vector Magnitude (EVM) is proposed to be a generic QoS trigger for
VHO execution. EVM is defined as the deviation of inphase/ quadrature (I/Q)
values from ideal signal states and thus provides a measure of signal quality.
In 4G Interoperable environment, OFDM is the leading Modulation scheme (more
prone to multi-path fading). EVM (modulation error) properly characterises the
wireless link/ channel for accurate VHO decision. EVM depends on the inherent
transmission impairments viz. frequency offset, phase noise,
non-linear-impairment, skewness etc. for a given wireless link. Paper provides
an insight to the analytical aspect of EVM & measures EVM (%) for key
management subframes like association/re-association/disassociation/ probe
request/response frames. EVM relation is explored for different possible
NAV-Network Allocation Vectors (frame duration). Finally EVM is compared with
SNR, BER and investigation concludes EVM as a promising QoS trigger for OFDM
based emerging wireless standards.Comment: 12 pages, 7 figures, IJWMN 2010 august issue vol. 2, no.
On the Minimization of Handover Decision Instability in Wireless Local Area Networks
This paper addresses handover decision instability which impacts negatively
on both user perception and network performances. To this aim, a new technique
called The HandOver Decision STAbility Technique (HODSTAT) is proposed for
horizontal handover in Wireless Local Area Networks (WLAN) based on IEEE
802.11standard. HODSTAT is based on a hysteresis margin analysis that, combined
with a utilitybased function, evaluates the need for the handover and
determines if the handover is needed or avoided. Indeed, if a Mobile Terminal
(MT) only transiently hands over to a better network, the gain from using this
new network may be diminished by the handover overhead and short usage
duration. The approach that we adopt throughout this article aims at reducing
the minimum handover occurrence that leads to the interruption of network
connectivity (this is due to the nature of handover in WLAN which is a break
before make which causes additional delay and packet loss). To this end, MT
rather performs a handover only if the connectivity of the current network is
threatened or if the performance of a neighboring network is really better
comparing the current one with a hysteresis margin. This hysteresis should make
a tradeoff between handover occurrence and the necessity to change the current
network of attachment. Our extensive simulation results show that our proposed
algorithm outperforms other decision stability approaches for handover decision
algorithm.Comment: 13 Pages, IJWM
Interworking Architectures in Heterogeneous Wireless Networks: An Algorithmic Overview
The scarce availability of spectrum and the proliferation of
smartphones, social networking applications, online gaming
etc., mobile network operators (MNOs) are faced with an
exponential growth in packet switched data requirements on
their networks. Haven invested in legacy systems (such as
HSPA, WCDMA, WiMAX, Cdma2000, LTE, etc.) that have
hitherto withstood the current and imminent data usage
demand, future and projected usage surpass the capabilities of the evolution of these individual technologies. Hence, a more critical, cost-effective and flexible approach to provide ubiquitous coverage for the user using available spectrum is of high demand. Heterogeneous Networks make use of these legacy systems by allowing users to connect to the best network available and most importantly seamlessly handover active sessions amidst them. This paper presents a survey of interworking architectures between IMT 2000 candidate networks that employ the use of IEFT protocols such as MIP, mSCTP, HIP, MOBIKE, IKEV2 and SIP etc. to bring about this much needed capacity
Proactive TCP mechanism to improve Handover performance in Mobile Satellite and Terrestrial Networks
Emerging standardization of Geo Mobile Radio (GMR-1) for satellite system is
having strong resemblance to terrestrial GSM (Global System for Mobile
communications) at the upper protocol layers and TCP (Transmission Control
Protocol) is one of them. This space segment technology as well as terrestrial
technology, is characterized by periodic variations in communication properties
and coverage causing the termination of ongoing call as connections of Mobile
Nodes (MN) alter stochastically. Although provisions are made to provide
efficient communication infrastructure this hybrid space and terrestrial
networks must ensure the end-to-end network performance so that MN can move
seamlessly among these networks. However from connectivity point of view
current TCP performance has not been engineered for mobility events in
multi-radio MN. Traditionally, TCP has applied a set of congestion control
algorithms (slow-start, congestion avoidance, fast retransmit, fast recovery)
to probe the currently available bandwidth on the connection path. These
algorithms need several round-trip times to find the correct transmission rate
(i.e. congestion window), and adapt to sudden changes connectivity due to
handover. While there are protocols to maintain the connection continuity on
mobility events, such as Mobile IP (MIP) and Host Identity Protocol (HIP), TCP
performance engineering has had less attention. TCP is implemented as a
separate component in an operating system, and is therefore often unaware of
the mobility events or the nature of multi-radios' communication. This paper
aims to improve TCP communication performance in Mobile satellite and
terrestrial networks.Comment: 5 pages, 2 figure
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