Radio propagation prediction for selected locations in Sun-U campus: a ray tracing approach using image method

Radio propagation prediction is a crucial step to determine the propagation characteristics of any arbitrary installation for the implementation of a mobile radio system. This is especially true for telecommunication systems that use electromagnetic waves for information transfer instead of relying on the conventional way that use electrical currents. In this paper, a ray tracing approach using image method is adopted to perform radio propagation predictions in two selected areas of Sun-U Campus, namely an empty hallway located on the second floor in the School of Computer Technology (SCT), and its adjacent academic staff rooms. The values of electrical parameter such as dielectric constant (relative permittivity) of different materials are altered assuming the walls that separate each academic staff room are made of rubber, glass, and plasterboard. How this variation affects radio wave propagation prediction is discussed while the main propagation mechanisms traveling along the empty hallway are reported

A ray tracing method for radio wave propagation prediction on selected locations on Sun-U campus

Radio propagation prediction is a crucial step to determine the propagation characteristics of any arbitrary installation for the implementation of a mobile radio system. In this paper, a ray tracing approach using image method is adopted to perform radio propagation predictions in two selected areas of Sun-U Campus, namely an empty hallway located on the second floor in the School of Computer Technology (SCT), and its adjacent academic staff rooms. The values of electrical parameter such as dielectric constant (relative permittivity) of different materials are altered assuming the walls that separate each academic staff room are made of rubber, glass, plasterboard, and concrete. How this variation affects radio wave propagation prediction is discussed while the main propagation mechanisms traveling along the empty hallway are reported. In addition, the reasons for an appropriate interval between two sampling points along a transmitter-receiver route are also illustrated and explained

Measurement arrangement for the estimation of path loss exponent in wireless sensor network

Path loss model is generally used to relate distance and signal strength in wireless applications. This has been widely implemented in ranging, localization, and location tracking systems. A range of extension models have been proposed to enhance the performance for various environments and applications. Nevertheless, path loss exponent remains its significance as the main factor in the model regardless of how the model is varied. Based on the nature as an exponent of the model, inaccurate path loss exponent amplifies the error if it is used to estimate distance from received signal strength. Therefore, measurement of accurate value for path loss exponent becomes very important as it directly influences the output of distance estimation. Researchers have been studying the methods of measuring accurate path loss exponent in various environments. Instead of emphasizing the calculation process, this paper focuses more on the allocation of transmitters and receivers, and the arrangement among them. From the results obtained from experiments, properly arranged transmitter and receiver nodes provides better estimation of the path loss exponent. Based on the results, this paper also proposes a suitable nodes arrangement scheme for path loss exponent estimation

Propagation measurement, drain, radio wave, electromagnetic, wireless communications.

Propagation measurement results were reported in a style of open-trench drain that is common in several Asian countries in [1]. In particular, measurement results at three frequencies, namely 900 MHz, 2.4 GHz, and 5.8 GHz were reported in three scenarios, whose findings are beneficial in designing wireless communication systems in environments where such drains are present. In this work, further investigation has been made on the contents inside an open-trench drain. This investigation is expected to contribute to a practically important propagation problem because in reality, the open-trench drains environments are not always dry and empty. On the contrary, they are sometimes filled with different contents, the most common one being water, as one of the primary objectives of a drain is to collect water runoff from the surrounding buildings and houses and convey it to an outfall. In other scenarios, the open-trench drain’s floor might be filled with liquids, soil, foliage from the surrounding trees, and even, trash

Measured radio wave behavior of a partially open drain in urban environment

This paper attempts to analyze the propagation characteristics of radio signal inside a partially open drain environment using an empirical approach. The proposed research topic concerns a unique situation in several Asian countries because the drainage systems in these countries differ notably from those in the US and Europe in that the former are partially open on the top while the latter are primarily below ground and covered. Measurement results are reported for one drain located on Sunway University campus at 2.4 and 5.8 GHz. The differences between the measurement results at the aforementioned two frequencies are discussed. These measurement results serve as a useful indicator as to how signal might behave differently in partially enclosed spaces, such as those where partially open drains exist, especially in an urban environment

Comparative effects of norepinephrine and vasopressin on internal thoracic arterial graft flow after off-pump coronary artery bypass grafting

ObjectiveVasoconstrictors such as norepinephrine and vasopressin are commonly used to raise the blood pressure during myocardial revascularization. The internal thoracic artery is commonly used for coronary artery grafting because of its long-term patency. However, the internal thoracic artery is a living conduit that responds to vasoactive substances. The objective of this study was to measure change in internal thoracic arterial flow after infusion of norepinephrine or vasopressin.MethodsForty-one patients undergoing elective off-pump coronary artery bypass grafting participated in this study. After the median sternotomy, the left internal thoracic artery was dissected with a pedicle and grafted to the left anterior descending artery. After all anastomoses were performed and hemodynamic parameters were stable, the grafted internal thoracic arterial blood flow was measured by transit time flowmeter on the distal portion of the graft as a baseline. Norepinephrine or vasopressin was then infused until mean arterial pressure was increased to 20% of baseline. Graft flow and hemodynamic variables were measured when mean arterial pressure reached the intended level.ResultsBaseline grafted internal thoracic arterial flows were similar (norepinephrine 57.1 ± 17.7 mL min−1, vasopressin 66.0 ± 34.3 mL min−1). With norepinephrine, flow increased significantly relative to baseline (77.2 ± 31.0 mL min−1); with vasopressin, it remained unchanged (68.3 ± 37.0 mL min−1).ConclusionsFor patients needing vasopressor support after coronary artery bypass grafting, norepinephrine appeared superior to vasopressin because of increased internal thoracic arterial flow

Method and and apparatus for processing a signal

A method of processing a signal is disclosed. The present invention includes receiving (a) downmix signal being generated from plural-channel signal and (b) spatial information indicating attribute of the plural-channel signal in order to upmix the downmix signal and including phase shift flag indicating whether phase of a frame of at least one channel of the plural-channel signal is shifted; obtaining inter-channel phase difference (IPD) coding flag indicating whether IPD value is used to the spatial information from a header of the spatial information; obtaining IPD mode flag indicating whether the IPD value is used to frame of the spatial information from the frame based on the IPD coding flag; obtaining the IPD value of parameter band in the frame, based on the IPD mode flag; upmixing plural-channel signal by applying the IPD value to the downmix signal; and shifting the phase of the frame of the at least one channel of the plural-channel signal based on the phase shift flag

Proposal for a local heating driven spin current generator

We propose a two-terminal spin-orbit interferometer with a hot molecule inserted in one of its arms to generate pure spin currents. Local heating is achieved by coupling the vibrational modes of the molecule to a third (phononic) reservoir. We show that this spin caloritronic effect is due to the combined influence of spin-dependent wave interference and inelastic scattering. Remarkably, the device converts heat flow into spin-polarized current even without applying any voltage or temperature difference to the electronic terminals. © 2013 AIP Publishing LLC.The authors acknowledge the support from MECD under Grant Nos. FIS2011-23526 and CSD2007-00042 (CPAN), and the National Research Foundation (NRF) grant funded by the Korea government (MSIP) (No. 2011-0030046).Peer Reviewe

Temperature dependence of Mott transition in VO_2 and programmable critical temperature sensor

The temperature dependence of the Mott metal-insulator transition (MIT) is studied with a VO_2-based two-terminal device. When a constant voltage is applied to the device, an abrupt current jump is observed with temperature. With increasing applied voltages, the transition temperature of the MIT current jump decreases. We find a monoclinic and electronically correlated metal (MCM) phase between the abrupt current jump and the structural phase transition (SPT). After the transition from insulator to metal, a linear increase in current (or conductivity) is shown with temperature until the current becomes a constant maximum value above T_{SPT}=68^oC. The SPT is confirmed by micro-Raman spectroscopy measurements. Optical microscopy analysis reveals the absence of the local current path in micro scale in the VO_2 device. The current uniformly flows throughout the surface of the VO_2 film when the MIT occurs. This device can be used as a programmable critical temperature sensor.Comment: 4 pages, 3 figure

Method and an apparatus for processing a signal

A method of processing a signal is disclosed. The present invention includes receiving a maximum number of band and a code value of at least one section length, calculating a bit number corresponding to the code value of the at least one section length using the maximum number of the band, and obtaining the section length information by decoding the code value of the section length based on the bit number. A method of processing a signal is disclosed. The present invention includes receiving factor information of a current frame, receiving flag information indicating whether a coding mode of the factor information is an absolute value mode or a relative value mode, and obtaining factor data of the current frame using factor data of a previous frame and the received factor information based on the flag information