Design and Analysis of the Key Management Mechanism in Evolved Multimedia Broadcast/Multicast Service

3GPP introduced the key management mechanism (KMM) in evolved multimedia broadcast/multicast service (eMBMS) to provide forward security and backward security for multicast contents. In this paper, we point out that KMM may lead to frequent rekeying and re-authentication issues due to eMBMS's characteristics: 1) massive group members; 2) dynamic group topology; and 3) unexpected wireless disconnections. Such issues expose extra load for both user equipment (UE) terminals and mobile operators. It seems prolonging the rekeying interval is an intuitive solution to minimizing the impact of the issues. However, a long rekeying interval is not considered the best operational solution due to revenue loss of content providers. This paper quantifies the tradeoff between the load of the UEs and the operators as well as the revenue loss of the content providers. Moreover, we emphasize how essential this rekeying interval has impacts on the problems. Using our proposed tradeoff model, the operators can specify a suitable rekeying interval to best balance the interest between the above three parties. The tradeoff model is validated by extensive simulations and is demonstrated to be an effective approach for the tradeoff analysis and optimization on eMBMS

A preliminary study on the dynamic friction behavior of a one-third scale-down vertical cylindrical cask

In Taiwan, the capacities of spent fuel pools for temporary storage in nuclear power plant will reach depletion soon, and the site of final disposal facility is still to be decided. Therefore, the installation of dry-type interim storage facilities is urgent. The dry storage systems in Taiwan utilize a freestanding cask and design to non-anchored to the foundation pad. It is necessary to establish the simulation techniques for the non-anchored structure, such as the dry storage cask, for the reasonable assessment of its seismic behavior when the earthquake hit. This study is cast a 1/3 scale-down pedestal specimen of the INER-dry storage cask system, which were conducted to acquire the actual friction coefficient at the cask/pad interface as well as the effect of normal stress and sliding rate on it. Based on the results of cyclic loading testing, the cyclic frequency almost had no influence on the friction coefficient but the friction coefficient increased with the normal stress increased. Apparent rocking of the cask was induced at a higher friction coefficient, while sliding dominated the cask motion at a lower one. In addition, the cast motions were almost purely sliding and the range of the friction coefficient was between 0.60 and 0.73 under various compositions of dry storage cask system

Mechanism of thermal field and electric field in resistive random access memory using the high/low-k side wall structure

In the Internet of things (IoT) era, low power consumption memory will be a critical issue for further device development. Among many kinds of next-generation memories, resistive random access memory (RRAM) is considered as having the most potential due to its high performance. To prevent unrecoverable hard break-down of a RRAM device, the RRAM should be collocated with a transistor for external current compliance. With decreasing device cell size, however, the operating voltage of the transistor will become smaller and smaller. Previous study has determined that the forming voltage of RRAM increases when device cell size is reduced, which is a very crucial issue especially when the device is scaled down. We have proposed a high-k sidewall spacer structure in RRAM to solve the dilemma of increasing forming voltages for device cell scaling down. Based on the COMSOL-simulated electrical field distributions in the high-k RRAM. In addition, thermal conductivity of sidewall spacer influenced resistive switching behavior. Suitable thermal conductivity of sidewall materials can enhance resistive switching behavior. Please click Additional Files below to see the full abstract

Actinomycosis of the Gallbladder: A Case Report

Introduction: Actinomycosis of the gallbladder is extremely rare and may mimic a malignancy leading to delayed diagnosis and/or inappropriate treatment.Presentation of case: Here we report the case of an 82-year-old man who presented with right upper abdominal discomfort for one month. Radiographically, an ill-defined mass was found in the gallbladder fossa that invaded the adjacent abdominal wall and liver bed. In addition, a stone was found in the gallbladder lumen. The imaging features suggested a gallbladder carcinoma. An initial CT-guided needle biopsy showed an inflammatory process. The subsequent open cholecystectomy revealed a contracted, thick-walled gallbladder surrounded by a soft tissue mass near the fundus. Histologically, the gallbladder revealed acute and chronic cholecystitis and microabscesses containing sulfur granules in the soft tissue mass, which showed Gram-positive filamentous bacilli. Under the diagnosis of gallbladder actinomycosis, the patient received post-operative antibiotics for 7 weeks and was well 5 months after diagnosis.Conclusion: Our case demonstrated that a gallbladder actinomycosis should be considered in the differential diagnosis in patients with cholelithiasis and cholecystitis presenting an invasive mass in the gallbladder fossa

The characterization of the saddle shaped nickel(III) porphyrin radical cation: an explicative NMR model for a ferromagnetically coupled metallo-porphyrin radical

Ni(III)(OETPP˙)(Br)2 is the first Ni(III) porphyrin radical cation with structural and (1)H and (13)C paramagnetic NMR data for porphyrinate systems. Associating EPR and NMR analyses with DFT calculations as a new model is capable of clearly determining the dominant state from two controversial spin distributions in the ring to be the Ni(III) LS coupled with an a1u spin-up radical

How Is the Sustainable Consumption Intention Model in Food Industry under Preference Uncertainties? The Consumer Willingness to Pay on Recycled Packaging Material

Food packaging is costly to consumers and generates a huge volume of packaging waste, especially in Indonesia. Prior studies have neglected to construct a causal sustainable consumption intention model in food industry and link to the consumer willingness to pay under preference uncertainties. To address the gaps, this study explores consumer attributes to build a causal sustainable consumption intention model and takes the model to address the consumer willingness to pay under preference uncertainties. This study proposes a causal model that integrates five aspects of sustainable consumption intention model: (1) sustainable consumption knowledge, attitudes, and behaviors; (2) government policy and regulation on sustainable consumption; (3) recycled packaging eco-labeling certification; (4) supply chain innovation and infrastructure; and (5) sustainable product purchasing features. This study uses the fuzzy Delphi method to confirm the reliability and validate the criteria and applies cause and effect model to address the causal model. In addition, this study collects 428 valid responses to address the willingness to pay for causal sustainable consumption intention model and a cognitive best-worst choice experiment to confirm the model in the food industry. The result reveals that recycled packaging eco-labeling certification is the major aspect for enhancing the model, followed by government policy and regulation and supply chain innovation and infrastructure. In practice, consumers incur inconvenience in purchasing sustainable food products but prefer recycled packaging material at a standardized price

In vivo sub-femtoliter resolution photoacoustic microscopy with higher frame rates

Microscopy based on non-fluorescent absorption dye staining is widely used in various fields of biomedicine for 400 years. Unlike its fluorescent counterpart, non-fluorescent absorption microscopy lacks proper methodologies to realize its in vivo applications with a sub-femtoliter 3D resolution. Regardless of the most advanced high-resolution photoacoustic microscopy, sub-femtoliter spatial resolution is still unattainable, and the imaging speed is relatively slow. In this paper, based on the two-photon photoacoustic mechanism, we demonstrated a in vivo label free laser-scanning photoacoustic imaging modality featuring high frame rates and sub-femtoliter 3D resolution simultaneously, which stands as a perfect solution to 3D high resolution non-fluorescent absorption microscopy. Furthermore, we first demonstrated in vivo label-free two-photon acoustic microscopy on the observation of non-fluorescent melanin distribution within mouse skin