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The proliferation of IoT devices comes with many challenges among which security is one of the most serious issues. In order to address the security issue for low-end IoT devices, ARM recently proposed the Platform Security Architecture (PSA), which provides execution isolation to safely manage and protect the computing resources of low-end IoT devices. However, developers implementing IoT services for PSA-based IoT devices need to follow complex development procedures and understand the PSA hardware, which dramatically increases the development time and cost of PSA-based IoT devices. This paper analyzes vulnerabilities that may arise from general purpose low-end IoT devices to derive the security requirements and essential security services for PSA-based IoT devices, and proposes a secure platform model based on the analysis results. The proposed secure platform model consists of system security services and application security services based on the basic PSA model and essential trusted sub-systems, and it is designed to be flexible and applicable to various types of PSA-based IoT devices. In addition, it provides secure platform services APIs to enable easy and fast development of IoT services. To evaluate the proposed secure platform model, two proof-of-concept implementations are provided by using both the basic PSA model with Secure Element (SE) and a reference device for ARM’s PSA. Finally, a case study shows that the development of IoT services can be done easily and quickly using the proposed security platform model.

A cognitive radio (CR) is a promising technology to solve the emerging spectrum crisis, especially for applications where thousands of wireless sensor nodes are deployed. Since continuous spectrum sensing will greatly reduce the lifetime of a network composed of energy-restricted CR nodes, an accurate method for predicting spectrum occupancy is necessary to improve energy efficiency. This paper proposes a hidden Markov model (HMM)-based cooperative spectrum sensing (CSS) that predicts the status of a network environment. The traditional prediction algorithms for cooperative spectrum sensing assume that all CR nodes have the same network environment. However, the channel availability of various CR nodes can be quite different, and thus the traditional algorithms will lead to low prediction accuracy in a complex radio environment. The proposed methods learn the historical spectrum sensing results and help the network to make an energy-efficient spectrum sensing decision. More specifically, the hidden state of HMM is set to different areas, where primary users (PUs) perform different activities. A Baum-Welch (BW) algorithm is employed to estimate the parameters of the HMM based on the past spectrum sensing results, and then the parameters are fed to a forward algorithm for the predicting of PUs' activity. Based on the prediction, secondary users (SUs) are classified into either ”interfered by PU” or ”not interfered by PU. ” The nodes selected as ”interfered by PU” will not perform spectrum sensing to reduce unnecessary energy consumption. The performance of the proposed method is evaluated using the simulations under different traffic conditions. The simulation results show that, compared with the conventional HMM-based methods, the effectiveness of the proposed algorithm in energy efficiency and spectrum utilization improved by about 13% and 15%, respectively.

Recently, cluster computer environments using multiple CPUs or multiple GPUs have been widely used to accelerate computation such as in the field of big data or artificial intelligence. In this paper, we propose an automatic computing device selection scheme between CPU and GPU by estimating the expected execution time based on trained deep learning model. Based on the experimental results, our scheme can select the computing device dynamically to reduce the execution time and maximize the computing efficiency.

To investigate the diagnostic value of computed tomography (CT) urography findings of anterior nutcracker syndrome (NCS).The study included patients with left renal vein (LRV) compression at the aortomesenteric portion at CT urography who underwent renal venography or cystoscopy. Patients with a renocaval pressure gradient of ≥3 mmHg on renal venography or bloody urine jetting from the left ureteral orifice on cystoscopy were defined as the NCS group; the remaining patients comprised the non-NCS group. CT findings were analysed using the jetting of contrast medium flow from the LRV to the inferior vena cava (jetting sign), aortomesenteric distance, presence of collateral veins, and a dilatation ratio of LRV diameter at the aortomesenteric portion (arterial phase/delayed phases). Clinical findings, including age, gender, and body-mass-index, were also analysed. CT features and clinical findings were compared between the NCS and non-NCS groups. Diagnostic performance of CT parameters was assessed using receiver operating characteristic curve analysis.A total of 70 patients (21 men, mean age 44.4 ± 17.2 years) with NCS (n=13) and non-NCS (n=57) were included. Younger age (40 years), presence of the jetting sign, and a lower dilatation ratio of LRV diameter between the arterial and delayed phases (1.7) were found to be significant independent factors for predicting the NCS group (OR 24.5, 18.9, 19.4, respectively, p0.05 for all). The combination of the presence of the jetting sign and a dilatation ratio of LRV diameter of1.7 obtained the highest AUC of 0.88.The jetting sign and the dilatation ratio of LRV diameter between the arterial and delayed phases can both be very useful in the diagnosis of anterior nutcracker syndrome during CT urography.

Recent IoT services are being used in various fields such as smart homes, smart factories, smart cars and industrial systems. These various IoT services are implemented through hyper-connected IoT devices, and accordingly, security requirements of these devices are being highlighted. In order to satisfy the security requirements of IoT devices, various studies have been conducted such as HSM, Security SoC, and TrustZone. In particular, ARM proposed Platform Security Architecture (PSA), which is a security architecture that provide execution isolation to safely manage and protect the computing resources of low- end IoT devices. PSA can ensure confidentiality and integrity of IoT devices based on its structural features, but conversely, it has the problem of increasing development difficulty in using the security functions of PSA. To solve this problem, this paper analyzes the security requirements of an IoT platform and proposes secure platform based on PSA. To evaluate the proposed secure platform, a PoC implementation is provided based on hardware prototype consisting of FPGA. Our experiments with the PoC implementation verify that the proposed secure platform offers not only high security but also convenience of application development for IoT devices.

Aim: The objective of this study was to develop a mitochondria-targeted anticancer drug, docetaxel (DTX), for chemotherapy. Materials & methods: The DTX was conjugated to 4-carboxybutyl triphenylphosphonium (TPP) to enhance mitochondrial targeting, and the TPP–DTX conjugate was further loaded into folate-cholesteryl albumin (FA-chol-BSA) nanoparticles (NPs) to improve its biocompatibility. Results & conclusion: In vitro studies showed that TPP–DTX and its NP primarily accumulated in the mitochondria; generated high reactive oxygen species, leading to mitochondrial disruption and cell apoptosis; and had a higher cytotoxicity against cancer cells. In vivo antitumor studies indicated that the NP significantly suppressed tumor growth compared with free drugs in xenograft tumor-bearing mice. Our results demonstrated that TPP–DTX@FA-chol-BSA NPs could be a promising mitochondria-targeted anticancer prodrug for chemotherapy.

The cognitive radio technology enables secondary users (SUs) to occupy licensed bands when primary users (PUs) are not occupy them. Spectrum sensing is a key technology for SUs to detect PUs, and the sensing time is a critical parameter for spectrum sensing performance. Optimum sensing time tradeoffs between the spectrum sensing performance and the secondary throughput. This paper proposes a novel spectrum sensing scheme that performs spectrum sensing for either one period or two periods based on the previous sensing result. Due to the energy constraint in cognitive radio sensor networks, the energy efficiency is maximized by optimizing spectrum sensing time. In order to seek the optimal sensing time, the objective function is proven to be a concave function and the Golden Section Search method is employed. Our simulation study verifies that the proposed scheme improves the network energy efficiency, especially when PUs are more active.

The cognitive radio (CR) technology allows secondary users (SUs) to occupy the licensed bands opportunistically without causing interferences to primary users (PUs). SUs perform spectrum sensing to detect whether PUs are busy or idle. Therefore, spectrum sensing directly affects the performance of the PU protection and the secondary throughput. The sensing time is a critical parameter for spectrum sensing performance, and the optimum sensing time is a tradeoff between the spectrum sensing performance and the secondary throughput. In this paper, a novel spectrum sensing scheme is proposed to maximize both sensing accuracy and network energy efficiency. In order to provide a better protection for the PU, another spectrum sensing is adaptively performed according to the first sensing result. In other words, SU will perform spectrum sensing again to confirm that the PU is indeed idle when the first sensing result indicates the PU is idle. Due to the energy constraint in CR sensor networks, this adaptive sensing interval can also be adjusted according to the varying activity of the PU to maximize the network energy efficiency. Finally, our simulation study validates that the proposed scheme improves both the spectrum sensing performance and the energy efficiency compared with other existing methods.

Wireless body area network (WBAN) is a communication technology, which aims providing both medical and consumer electronics services through sensor devices in, on, or around a human body. Due to the absence of the IEEE 802.15.6-based RF modules, the IEEE 802.15.4, a typical low-power communication technology of which requirements are similar, is considered to implement WBANs. In the case where a lot of WBANs coexist, meanwhile, collisions and signal attenuations may lead to their communication performance degradation. However, the IEEE 802.15.4 does not provide any solutions to solve coexistence problems, and thus, coexistence mitigation schemes for the IEEE 802.15.4-based WBANs are necessary. In this paper, we perform preliminary experiments to identify aspects of coexistence problem among the coexisting IEEE 802.15.4-based WBANs. Based on the results of preliminary experiments, we also propose a hybrid channel access scheme to mitigate coexistence problems in WBANs. The proposed scheme can be classified into two phases. In the first phase, the proposed scheme provides probabilistic collision avoidance on the contention-free period. When the pre-defined requirements of reliability cannot be satisfied with performing the first phase, the proposed scheme performs the second phase, which helps to mitigate collision or interference through changing channel access method. To evaluate the performance of the proposed scheme, we implement our scheme and perform experiments by comparing with an IEEE 802.15.4-based WBAN.

The recent ASCE report card gave a "D" grade for the state of drinking water infrastructure in the U.S. and reported that there are about 240,000 water main failures annually. Some of these failures result in significant economic, environmental and societal consequences that are difficult to predict for the purpose of accurate risk assessment and subsequent rehabilitation planning. This study analyzed the overall consequences of 20 large diameter water main failures in the U.S., majority of which have occurred in the last seven years, with an objective of identifying factors that aggravate the consequences to be able to reasonably predict them for rehabilitation decision making. It has been found that the overall cost of the failure consequences dependedon several factors that include but not limited to pipeline size, relative elevation and the type of land use, population density, utility response and repair time, and operating pressure. Direct repair of the failed pipeline, followed by property damage and then travel delays, accounted for 35%, 22% and 21% of the overall failure cost on average, respectively. It has also been found that the direct costs which the water utility pays for accounted for only about 41% while the indirect costs which are usually borne by the society accounted for the remaining 59%. While consideration of the overall failure costs as part of rehabilitation planning may increase the investment needs of water utilities, it remains to be investigated as to how much more investment will be required, who would pay for it and how willing are the water utilities in adopting the overall failure cost approach.

In a wireless body area network (WBAN), high data reliability and long operating time are important requirements. The retransmission process of the default Automatic Repeat reQuest (ARQ) mechanism in IEEE 802.15.4 is a suitable method to ensure the data reliability of WBAN communications, where frame loss can occur frequently. However, retransmitting the entire DATA frame is energy inefficient due to the fact that the most of payload data within lost frames are only partially corrupted. Therefore, this paper proposes the automatic segment repeat request scheme for the IEEE 802.15.4-based WBANs. The proposed scheme partitions the data payload into segments when the channel condition is bad, and retransmits only the corrupted segment(s). This reduces the size of the retransmitted frames, which improves frame reception rate and decreases the amount of transmitted traffic, and thus energy consumption. Our experiments using a real IEEE 802.15.4-based WBAN test bed show that the proposed method provides higher transmission reliability and lower power consumption than the default IEEE 802.15.4 ARQ mechanism.

Neuromorphic computing or neuromorphic engineering is an engineering discipline that attempts to simulate human brain function by creating circuits that mimic the shape of neurons. In the field of neuromorphic computing, neuromorphic processors are used. There are many types of neuromorphic processors, and there are neuromorphic processors implemented based on FPGAs. Neuromorphic processors use an artificial intelligence model called a spiking neural network. Each neuromorphic processor has different characteristics. For example, the spiking neural network model supported by each supported neuromorphic processor may be different. In this paper, we propose a service architecture named NAAL (Neuromorphic Architecture Abstract Layer) that enables the use of spiking neural networks by virtualizing various neuromorphic processors with different characteristics.

인지 무선 센서 네트워크 (CRSNs)에서 보조 사용자가 (SUs) 주 사용자 (PUs)에 간섭을 주지 않고 기회주의적 방식으로 라이선스 대역을 사용할 수 있다. SUs가 스펙트럼 센싱을 통해 PU의 존재 여부를 확인할 수 있다. 그리고 센싱 시간은 스펙트럼 센싱의 중요한 파라미터이다. 센싱 시간은 센싱 성능과 스루풋 간의 균형을 얻을 수 있다. 본 논문에서는 다른 관점에서 이 균형을 탐구하기를 통해 스펙트럼 센싱을 위한 새로운 기법을 제안한다: a) PU의 검출 (SSPD)과 b)스루풋(SSST)을 극대화을 위한 스펙트럼 센싱이다. 제안한 기법에서 현재 프레임의 첫 번째 센싱 결과에 따라 동적인 두 번째 스펙트럼 센싱을 수행한다. CRSNs에서 에너지 제약을 때문에 네트워크 에너지 효율도 센싱 시간의 최적화를 통해 최대화된다. 시뮬레이션 결과를 통하여 제안된 SSPD과 SSST가 각각의 에너지 효율과 스루풋의 성능을 향상시킬 수 있음을 검증하였다.

A Wireless body area network (WBAN) is a communication network that provides both medical and consumer electronics services by using sensors in/on/around a human body. In general, a WBAN environment suffers from frequent link loss due to interferences among sensors scattered over a body. In addition, the channel condition can frequently change by postural body movement, which increases packet drops, retransmissions, and eventually power consumption. This paper presents an Analytical Hierarchy Process (AHP)-based flexible relay node selection scheme that considers a multitude of decision factors, such as average SNR, remaining energy ratio, and traffic load. Moreover, the proposed scheme can adaptively satisfy the requirements of WBAN in various scenarios. Our simulation study shows that the proposed method provides high communication reliability and low power consumption.

인지 무선 기술은 보조 사용자가 (SUs) 주 사용자 (PUs)에 간섭을 주지 않고 기회주의적 방식으로 라이선스 스펙트럼을 사용할 수 있는 기술이다. 인지 라디오의 핵심 기술은 스펙트럼 센싱이다. 그러나 인지 무선 센서 네트워크에서 에너지 효율적인 스펙트럼 센싱 기법에 대한 연구는 많지 않다. 본 논문에서는 클러스터 기반의 인지 무선 센서 네트워크를 위한 에너지 효율적인 협력 스펙트럼 센싱 노드 선택 기법을 제안한다. 제안하는 기법에서, 허위 경보 확률 및 에너지 소비를 최적화하기 위하여 클러스터내 스펙트럼 센싱 노드들의 수를 최소화하게 된다. 시뮬레이션 결과를 통하여 본 논문에서 제안한 최적의 스펙트럼 센싱 노드 수를 적용하므로 스펙트럼 센싱 효율성이 향상되었고, 또한 네트워크의 에너지 효율성도 보장된 것을 검증하였다.

In densely located loosely coupled wireless charger environments, cross-connection errors can occur when wireless chargers operate at the same time within the same wireless communication range. In this work, an effective algorithm is proposed to prevent cross-connection error. The algorithm based on the cross-connection abatement technique with the received signal strength indicator of out-band BLE communication has improved using an in-band magnetic field signal controlled by a pulse-width-modulation-like waveform. The experimental results obtained from a proper test set in a RF shield room verify that the wireless charging system using the proposed algorithm provides wireless charging services without cross-connection errors.

The blood-brain barrier (BBB) is a limiting factor in nanoparticle drug delivery to the brain, and various attempts have been made to overcome it for efficient drug delivery. Nowadays, it was considered as further issue for brain-drug delivery that the nanoparticle delivered to brain through the BBB reach cancer cells in tumour tissue. In this study, we investigated the effect of nanoparticle size on blood-brain tumour barrier (BBTB) permeation of fluorescence-labelled gold nanoparticles (AuNPs) in a mouse model of orthotopic glioblastoma multiforme (GBM), established by intracranial implantation of luciferase-expressing human glioblastoma U87MG cells. AuNPs sized 10, 50, and 100 nm were perfused into the GBM mice via internal carotid artery (ICA) for 5 min. Immediately after perfusion, the brains were fixed and prepared for LSCM observation. The AuNPs distribution in the normal and tumorous brain tissues was analysed qualitatively and quantitatively. Higher distribution of AuNPs was observed in the tumorous tissue than in the normal tissue. Furthermore, the smallest nanoparticle, 10 nm AuNPs, was widely distributed in the brain tumour tissue, whereas the 50 and 100 nm AuNPs were located near the blood vessels. Therefore, nanoparticle size affected the permeation of nanoparticles from the blood into brain tumour tissue.

In wireless sensor networks, clustering schemes have been adopted as an efficient solution to prolong the network lifetime. In these schemes, the performance of energy-efficient data transmission is affected the cluster ratio (CR). This paper analyzes the optimal CR from the perspective of network energy efficiency, and its impact on the network lifetime. In order to provide a generic analytic model, various data propagation cases are mathematically analyzed. In addition, the network lifetime is extended by jointly optimizing the network transmission count and link reliability. Our simulation results show that the optimal CR derived based on the proposed analytical model enhances the energy efficiency and effectively increases the network lifetime.

WBAN(Wireless Body Area Network) operating around the human body aims at medical and non-medical service at the same time. and it is the short-range communication technology requiring lo w-power, various data rate and high reliability. Various studie s is performing for IEEE 802.15.4, because IEEE 802.15.4 can provide high compatibility for operate WBAN among communication standa rd satisfiable these requirements. Meanwhile, in the case of coexi sting many IEEE 802.15.4-based WBAN, signal interference and co llision are the main cause that is decreasing data reliability. but IEE E 802.15.4 Standard does not consider about coexistence of many networks. so it needs improvement. In this paper, To solve abou t this problem, identify coexistence problem of IEEE 802.15.4-b ased WBAN by preliminary experiments. and propose a scheme to mitiga te the reliability decrease at multiple coexistence WBAN. The proposed scheme can be classified in two steps. The first step is avoidance to collision on the CFP through improving data tra nsmission. The second step is mitigation collision through converting chan nel access method. Proposed scheme is verified the performance by performing comparison experiment with Standard-based WBAN.

To provide scalability, wireless sensor network has cluster-based architecture. Wireless sensor network can be implemented based on the IEEE 802.15.4 which is exploited in 2.4GHz ISM frequency band. Since this frequency band is used for various data communication, network status of wireless sensor networks frequently changes according to wireless environment. Thus, wireless channel selection to avoid reduction of transmission efficiency is required. This paper estimates network status using the information that a cluster-head collects in a cluster. Through objective function with throughput, RSSI level and reliability as input parameters, this paper proposes proper wireless channel selection. Simulation results show that the proposed method maintains transmission efficiency even though network status changes.

In public environments where LC wireless charging pads and charging devices are dense, cross-connection errors between the wireless charging pads and charging devices can occur within the same short-range wireless communication range. In this work, an effective cross-connect abatement technique using a received signal strength indicator (RSSI) signal and an in-band magnetic field signal modulated by a pulse with modulation (PWM)-like waveform is proposed to prevent cross-connection errors. The experimental results in dense LC wireless charging pad environments show that the proposed technique provides stable wireless charging services without cross-connection errors.