Analysis of detection performance in spectrum sensing optimisation for long sensing periods

Spectrum sensing optimisation techniques maximise the efficiency of spectrum sensing while satisfying a number of constraints. Many optimisation models consider the possibility of the primary user changing activity state during the secondary user's transmission period. However, most ignore the possibility of activity change during the sensing period. The observed primary user signal during sensing can exhibit a duty cycle which has been shown to severely degrade detection performance. This paper shows that (a) the probability of state change during sensing cannot be neglected and (b) the true detection performance obtained when incorporating the duty cycle of the primary user signal can deviate significantly from the results expected with the assumption of no such duty cycle.

Property Agents and Motor Dealers Act : strike three

The Tourism, Racing and Fair Trading (Miscellaneous Provisions) Act 2002 (“the Act”) which was passed on 18 April 2002 contains a number of significant amendments relevant to the operation of the Property Agents and Motor Dealers Act 2000. The main changes relevant to property transactions are: (i) Changes to the process for appointment of a real estate agent and consolidation of the appointment forms; (ii) Additions to the disclosure obligation of agents and property developers; (iii) Simplification of the process for commencing the cooling off period; (iv) Alteration of the common law position concerning when the parties are bound by a contract; (v) Removal of the requirement for a seller’s signature on the warning statement to be witnessed; (vi) Retrospective amendment of s 170 of the Body Corporate and Community Management Act 1997; (vii) Inclusion of a new power to allow inspectors to enter the place of business of a licensee or a marketeer without consent and without a warrant; and (viii) Inclusion of a new power for inspectors to require documents to be produced by marketeers. The majority of the amendments are effective from the date of assent, 24 April 2002, however, some of the amendments do not commence until a date fixed by proclamation. No proclamation has been made at the time of writing (2 May 2002). Where the amendments have not commenced this will be noted in the article. Before providing clients with advice, practitioners should carefully check proclamation details.

Property Agents and Motor Dealers Act : take two

The Property Agents and Motor Dealers Act 2000 commenced on 1 July 2001. Significant changes have now been made to the Act by the Property Agents and Motor Dealers Amendment Act 2001 (“the amending Act”). The amending Act contains two distinct parts. First, ss 11-19 of the amending Act provide for increased disclosure obligations on real estate agents, property developers and lawyers together with an extension of the 5 business day cooling-off period imposed by the original Act to all residential property (other than contracts formed on a sale by auction). These provisions commenced on 29 October 2001. The remaining provisions of the amending Act provide for increased jurisdiction and powers to the Property Agents and Motor Dealers Tribunal (“the Tribunal”) enabling the Tribunal to deal with claims against marketeers. These provisions commenced on the date of assent, 21 September 2001.

Causing economic harm to property developers : damages for starting an incurably bad appeal?

A recent decision of the Queensland Court of Appeal involved an unusual statement of claim made on behalf of the developer of a proposed resort in Port Douglas. The decision is The Beach Club Port Douglas Pty Ltd v Page [2005] QCA 475. The issue The defendant had objected to a development application of the plaintiff developer and lodged an appeal in the Planning and Environment Court against the council decision granting a development permit. The main issue in the Planning and Environment Court was whether the site coverage of the proposed resort was excessive. In a separate action (the subject matter of the present appeal), the plaintiff developer claimed damages for ‘negligence’ alleging that the defendant had breached a duty of care not to appeal without properly or reasonably assessing whether the development qualified for a permit given that the resort qualified for the maximum allowable site coverage. It was alleged that the appeal lodged by the defendant in the Planning and Environment Court had no reasonable prospects of success and that any reasonable person properly advised would know, or ought reasonably to have known, that to be so. The defendant had been “put on notice” that the plaintiff would incur loss of $10,000 for every day there was a delay in starting construction of the resort. The claim made by the developer required the court to consider those circumstances where a person may lawfully and deliberately cause economic harm to another. Was a duty of care owed by the defendant for negligent conduct of litigation that caused economic loss to the plaintiff?

Using reputation management in participatory sensing for data classification

Participatory sensing enables collection, processing, dissemination and analysis of environmental sensory data by ordinary citizens, through mobile devices. Researchers have recognized the potential of participatory sensing and attempted applying it to many areas. However, participants may submit low quality, misleading, inaccurate, or even malicious data. Therefore, finding a way to improve the data quality has become a significant issue. This study proposes using reputation management to classify the gathered data and provide useful information for campaign organizers and data analysts to facilitate their decisions.

Waiver of statutory requirements : Property Agents and Motor Dealers Act 2000 (Qld)

One of the many difficulties associated with the drafting of the Property Agents and Motor Dealers Act 2000 (Qld) (‘the Act’) is the operation of s 365. If the requirements imposed by this section concerning the return of the executed contract are not complied with, the buyer and the seller will not be bound by the relevant contract and the cooling-off period will not commence. In these circumstances, it is clear that a buyer’s offer may be withdrawn. However, the drafting of the Act creates a difficulty in that the ability of the seller to withdraw from the transaction prior to the parties being bound by the contract is not expressly provided by s 365. On one view, if the buyer is able to withdraw an offer at any time before receiving the prescribed contract documentation the seller also should not be bound by the contract until this time, notwithstanding that the seller may have been bound at common law. However, an alternative analysis is that the legislative omission to provide the seller with a right of withdrawal may be deliberate given the statutory focus on buyer protection. If this analysis were correct the seller would be denied the right to withdraw from the transaction after the contract was formed at common law (that is, after the seller had signed and the fact of signing had been communicated to the buyer).

Property Agents and Motor Dealers Act (Qld) : disclosure, cooling-off and marketeers

The Property Agents and Motor Dealers Act 2000 commenced on 1 July 2001. Significant changes have now been made to the Act by the Property Agents and Motor Dealers Amendment Act 2001 (“the amending Act”). The amending Act contains two distinct parts. First, ss 11-19 of the amending Act provide for increased disclosure obligations on real estate agents, property developers and lawyers together with an extension of the 5 business day cooling-off period imposed by the original Act to all residential property (other than contracts formed on a sale by auction). These provisions are expected to commence on 29 October 2001. The remaining provisions of the amending Act provide for increased jurisdiction and powers to the Property Agents and Motor Dealers Tribunal (“the Tribunal”) enabling the Tribunal to deal with claims against marketeers. These provisions commenced on the date of assent (21 September 2001).

Can compensation be claimed under the standard commercial land and building contract where the property sold has no legally enforceable vehicular access?

This was the question that confronted Wilson J in Jarema Pty Ltd v Michihiko Kato [2004] QSC 451. Facts The plaintiff was the buyer of a commercial property at Bundall. The property comprised a 6 storey office building with a basement car park with 54 car parking spaces. The property was sold for $5 million with the contract being the standard REIQ/QLS form for Commercial Land and Buildings (2nd ed GST reprint). The contract provided for a “due diligence” period. During this period, the buyer’s solicitors discovered that there was no direct access from a public road to the car park entrance. Access to the car park was over a lot of which the Gold Coast City Council was the registered owner under a nomination of trustees, the Council holding the property on trust for car parking and town planning purposes. Due to the absence of a registered easement over the Council’s land, the buyer’s solicitors sought a reduction in the purchase price. The seller would not agree to this. Finally the sale was completed with the buyer reserving its rights to seek compensation.

Transition from n- to p-type of spray pyrolysis deposited Cu doped ZnO thin films for NO2 sensing

The structural, optical, and gas-sensing properties of spray pyrolysis deposited Cu doped ZnO thin films were investigated. Gas response of the undoped and doped films to N02 (oxidizing) gas shows an increase and decrease in resistance, respectively, indicating p-type conduction in doped samples. The UV-Vis spectra of the films show decrease in the bandgap with increasing Cu concentration in ZnO. The observed p-type conductivity is attributed to the holes generated by incorporated Cu atoms on Zn sites in ZnO thin films. The X-ray diffraction spectra showed that samples are polycrystalline with the hexagonal wurtzite structure and increasing the concentration of Cu caused a decrease in the intensity of the dominant (002) peak. The surface morphology of films was studied by scanning electron microscopy and the presence of Cu was also confirmed by X-ray photoelectron spectroscopy. Seebeck effect measurements were utilized to confirm the p-type conduction of Cu doped ZnO thin films. Copyright © 2009 American Scientific Publishers All rights reserved.

Reversed bias Pt/nanostructured ZnO Schottky diode with enhanced electric field for hydrogen sensing

In this paper, the effect of electric field enhancement on Pt/nanostructured ZnO Schottky diode based hydrogen sensors under reverse bias condition has been investigated. Current-voltage characteristics of these diodes have been studied at temperatures from 25 to 620 °C and their free carrier density concentration was estimated by exposing the sensors to hydrogen gas. The experimental results show a significantly lower breakdown voltage in reversed bias current-voltage characteristics than the conventional Schottky diodes and also greater lateral voltage shift in reverse bias operation than the forward bias. This can be ascribed to the increased localized electric fields emanating from the sharp edges and corners of the nanostructured morphologies. At 620 °C, voltage shifts of 114 and 325 mV for 0.06% and 1% hydrogen have been recorded from dynamic response under the reverse bias condition. © 2010 Elsevier B.V. All rights reserved.

Nanowires of metal oxides for gas sensing applications

Nanowires of different metal oxides (SnO2, ZnO) have been grown by evaporation-condensation process. Their chemical composition has been investigated by using XPS. The standard XPS quantification through main photoelectron peaks, modified Auger parameter and valence band spectra were examined for the accurate determination of oxidation state of metals in the nanowires. Morphological investigation has been conducted by acquiring and analyzing the SEM images. For the simulation of working conditions of sensor, the samples were annealed in ultra high vacuum (UHV) up to 500°C and XPS analysis repeated after this treatment. Finally, the nanowires of SnO 2 have were used to produce a novel gas sensor based on Pt/oxide/SiC structure and operating as Schottky diode. Copyright © 2008 John Wiley & Sons, Ltd.