Very recently, Alamr et al (J. Supercomput 1‐14 doi: 10.1007/s11227‐016‐1861‐1) presented a radio frequency identifier (RFID) authentication protocol for the Internet of Things (IoT) through elliptic curve cryptography (ECC). They claimed the protocol to achieve several security properties and thwart all known attacks. However, this paper shows that their scheme is having correctness and scalability issues. The reader in their protocol can accommodate only one tag, which is not desirable in the IoT environments. The paper finally suggests an improvement to cater the correctness and scalability issues. 相似文献
Pristine Ni/γ–Al2O3 and CeO2–Ni/γ–Al2O3 catalysts were prepared by co-impregnation technique for dry reforming of propane. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) were used to examine the structure and morphology of the catalysts before and after the reforming reactions. The excellent interaction between catalyst active phases was observed in both CeO2–Ni/γ–Al2O3 and Ni/γ–Al2O3 stabilized with polyethelene glycol (Ni/γ–Al2O3–PEG). Towards C3H8 and CO2 conversion, the CeO2–Ni/γ–Al2O3 and Ni/γ–Al2O3–PEG showed improved catalytic activity when compared to the pristine Ni/γ–Al2O3 catalyst. Interestingly, high H2 concentration was achieved with the CeO2–Ni/γ–Al2O3 and high CO concentration with the Ni/γ–Al2O3–PEG, which is due to the nanoconfinement of nickel particles within the support and favorable metal-support interaction as a result of plasma reduction. The CeO2–Ni/γ–Al2O3 catalyst exhibited better stability for anti-sintering and coke resistance, thus exhibiting high reactivity and durability in the dry reforming. 相似文献
The present study investigates the effect of Pithecellobium dulce biodiesel (PDBD) blends with diesel fuel on compression ignition (CI) engine emissions. Initially, PDBD was prepared by using a base transesteri?cation process. The GC‐MS, 1H NMR, and Fourier transform infrared characterization of PDBD was carried out, and fuel properties were determined. The experiments were conducted on a single cylinder, CI engine using three blended fuels: PDBD5 (5% biodiesel and 95% diesel), PDBD10 (10% biodiesel and 90% diesel), and PDBD20 (20% biodiesel and 80% diesel). The experimental outcomes revealed that 20% of PDBD reduces 19.64% carbon monoxide, 17.64% hydrocarbon, and 6.73% oxides of nitrogen emissions. Furthermore, from this study, it was inferred that the PDBD20 blend could be used as an alternative fuel for CI engines with no modi?cations in engine design. 相似文献
Wireless body area network (WBAN) is utilized in various healthcare applications due to its ability to provide suitable medical services by exchanging the biological data between the patient and doctor through a network of implantable or wearable medical sensors connected in the patients’ body. The collected data are communicated to the medical personals through open wireless channels. Nevertheless, due to the open wireless nature of communication channels, WBAN is susceptible to security attacks by malicious users. For that reason, secure anonymous authentication and confidentiality preservation schemes are essential in WBAN. Authentication and confidentiality play a significant role while transfers, medical images securely across the network. Since medical images contain highly sensitive information, those images should be transferred securely from the patients to the doctor and vice versa. The proposed anonymous authentication technique helps to ensure the legitimacy of the patient and doctors without disclosing their privacy. Even though various cryptographic encryption techniques such as AES and DES are available to provide confidentiality, the key size and the key sharing are the main problems to provide a worthy level of security. Hence, an efficient affine cipher-based encryption technique is proposed in this paper to offer a high level of confidentiality with smaller key size compared to existing encryption techniques. The security strength of the proposed work against various harmful security attacks is proven in security analysis section to ensure that it provides better security. The storage cost, communication cost and computational cost of the proposed scheme are demonstrated in the performance analysis section elaborately. In connection to this, the computational complexity of the proposed scheme is reduced around 29% compared to the existing scheme.
APAN [4] has native IPv6 network across all major APAN exchange points. It is important to validate the performance of the links in the network to ensure the link stability. This paper discusses the technique and mechanism that are used to perform online monitoring of the APAN IPv6 network status. Pchar tool is used to check the performance of the network. Metrics such as bandwidth, hop count and round trip time between nodes in each country's have been adopted for these monitoring activity. 相似文献
A compact add-on objective lens for the scanning electron microscope (SEM) has been designed and tested. The lens is < 35 mm high and can be fitted on to the specimen stage as an easy-to-use attachment. Initial results show that it typically improves the spatial resolution of the SEM by a factor of three. The add-on unit is based upon a permanent magnet immersion lens design. Apart from the extra attachment to the specimen stage, the SEM with the add-on lens functions in the normal way. The in-lens unit can comfortably accommodate specimen heights up to 10 mm. The new add-on lens unit opens up the possibility of operating existing SEMs in the high-resolution in-lens mode. By using a deflector at the top of the add-on lens unit, it can also operate as a quantitative multichannel voltage contrast spectrometer, capable of recording the energy spectrum of the emitted secondary electrons. Initial experiments confirm that a significant amount of voltage contrast can be obtained. 相似文献