This letter describes combining OSGi and Web Services in service composition. According to our approach, a composite service is described in WS-BPEL. Each component service in the description may be resolved to either an OSGi service or Web Service at runtime. The proposal can overcome current limitations with OSGi technology in terms of its geographical coverage and candidate service population available for service composition.

This paper presents a method to improve field uniformity using two TX antennas in a reverberation chamber with less steps of a stirrer. A mode-stirred reverberation chamber (MSRC) is considered as an alternative to the semi-anechoic chamber for an electromagnetic compatibility test because it provides a large test volume, a statistically uniform field, and a high maximum electric field. To improve field uniformity, we introduce two transmitting antennas for excitation in an MSRC, and predict statistical distribution of the complex reflection coefficients (scattering parameters). To prove the validation of our theory and the reliability of measurement results, three kinds of stirrers with different shape and sizes were fabricated and their efficiencies were measured in an MSRC, and then field uniformities have been investigated for 1–3 GHz frequency within the maximum number of independent samples that stirrers can provide. The measurement results show that the average received power is about 1.5 times as high as when using one transmitting antenna, and field uniformity is improved. Use of two transmitting antennas in an MSRC is regarded as a useful method to improve field uniformity at less stirrer steps, for radiated immunity tests.

This letter presents a new gossip-based ad hoc service discovery protocol that uses a novel decentralized, peer-to-peer mechanism to provide mobile devices with the ability to advertise and discover services in an efficient way. Our performance study shows that the proposed protocol appropriately addresses the need of proximal service discovery over a dynamic wireless medium.

Smart cities aim to improve the quality of life of citizens and efficiency of city operations through utilization of 5G communication technology. Based on various technologies such as IoT, cloud computing, artificial intelligence, and big data, they provide smart services in terms of urban planning, development, and management for solving problems such as fine dust, traffic congestion and safety, energy efficiency, water shortage, and an aging population. However, as smart city has an open network structure, an adversary can easily try to gain illegal access and perform denial of service and sniffing attacks that can threaten the safety and privacy of citizens. In smart cities, the global mobility network (GLOMONET) supports mobile services between heterogeneous networks of mobile devices such as autonomous vehicles and drones. Recently, Chen et al. proposed a user authentication scheme for GLOMONET in smart cities. Nevertheless, we found some weaknesses in the scheme proposed by them. In this study, we propose a secure lightweight authentication for roaming services in a smart city, called SLARS, to enhance security. We proved that SLARS is more secure and efficient than the related authentication scheme for GLOMONET through security and performance analysis. Our analysis results show that SLARS satisfies all security requirements in GLOMONET and saves 72.7% of computation time compared to that of Chen et al.’s scheme.

A backdoor sample attack is an attack that causes a deep neural network to misrecognize data that include a specific trigger because the model has been trained on malicious data that insert triggers into the deep neural network. The deep neural network correctly recognizes data without triggers, but incorrectly recognizes data with triggers. These backdoor attacks have mainly been studied in the image domain; however, defense research in the text domain is insufficient. In this study, we propose a method to defend against textual backdoor samples using a detection model. The proposed method detects a textual backdoor sample by comparing the resulting value of the target model with that of the model trained on the original training data. This method can defend against attacks without access to the entire training data. For the experimental setup, we used the TensorFlow library, and the MR and IMDB datasets were used as the experimental datasets. As a result of the experiment, when 1000 partial training datasets were used to train the detection model, the proposed method could classify the MR and IMDB datasets with detection rates of 79.6% and 83.2%, respectively.

This letter proposes a new mechanism for network configuration on a mobile device that provides Point of Attachment (PoA) specific information using IEEE 802.21 and DHCP before moving to a new PoA. This allows the mobile device to prepare for intelligent handover decision either stateless address configuration or stateful address configuration when entering an IPv6 network. It allows the mobile device to reduce time delay for IP address configuration in the new PoA. Implementation and evaluation results show that the proposed mechanism can be an acceptable network configuration mechanism for providing seamless television watching in IPv6 mobile networks, even when in motion.

The performance of a network router/switch has improved significantly over past decades with explosively increasing internet and data center traffic. The performance of a router heavily depends on the memory system, e.g. DRAM based packet buffers, which often limits the scalability of a router. However, a widening gap between memory I/O bus and memory cell array speed and decreasing row buffer locality from increasing channels and banks severely reduce the performance gain from state-of-the-art memory technology such as DDR4 or HBM2 DRAM. Prior works improved memory bandwidth by maintaining SRAM-based per-queue or per-bank input/output buffers in the memory controller to support a DRAM-based packet buffer. The buffers temporarily store packets when bank conflicts occur but are unable to prevent interference-inducing traffic from thrashing DRAM's row buffers. In this study, we directly integrate SRAM into the DRAM-based packet buffer and map those packets degrading row buffer locality of DRAM into SRAM. This maximizes locality and parallelism of DRAM accesses. The proposed scheme can benefit any existing schemes. Experimental results show 22.41% improvement over the best existing scheme for a single channel in terms of the memory bandwidth utilization under harsh congested scenarios.

Mobile ad-hoc networks consist of mobile nodes interconnected by multihop path that has no fixed network infrastructure support. Due to the limited bandwidth and resource, and also the frequent changes in topologies, ad-hoc network should consider these features for the provision of security. We present a secure routing protocol based on identity-based signcryption scheme. Since the proposed protocol uses an identity-based cryptosystem, it does not need to maintain a public key directory and to exchange any certificate. In addition, the signcyption scheme simultaneously fulfills both the functions of digital signature and encryption. Therefore, our protocol can give savings in computation cost and have less amount of overhead than the other protocols based on RSA because it uses identity-based signcryption with pairing on elliptic curve. The effectiveness of our protocol is illustrated by simulations conducted using ns-2.

With the proliferation of smart grids and the construction of various electric IT systems and networks, a next-generation substation automation system (SAS) based on IEC 61850 has been agreed upon as a core element of smart grids. However, research on security vulnerability analysis and quantification for automated substations is still in the preliminary phase. In particular, it is not suitable to apply existing security vulnerability quantification approaches to IEC 61850-based SAS because of its heterogeneous characteristics. In this paper, we propose an IEC 61850-based SAS network modeling and evaluation approach for security vulnerability quantification. The proposed approach uses network-level and device groupings to categorize the characteristic of the SAS. In addition, novel attack scenarios are proposed through a zoning scheme to evaluate the network model. Finally, an MTTC (Mean Time-to-Compromise) scheme is used to verify the proposed network model using a sample attack scenario.

A novel one-transistor dynamic random access memory (1T DRAM) cell has been proposed for a low-voltage operation and longer data retention time. The proposed 1T DRAM cell has three features compared with a conventional 1T DRAM cell: low body doping concentration, a recessed gate structure, and a P + poly-Si gate. Simulation results show that the proposed 1T DRAM cell has < 1-ns program time and > 100-ms data retention time under the condition of sub-1-V operating voltage.

In this letter, we propose a new preamble structure for channel estimation in a MIMO OFDM-based WLAN system. Both backward compatibility with IEEE 802.11a and low overhead are considered in designing the preamble. Simulation results show that the proposed preamble has low overhead and good performance gain for channel estimation.

This paper presents novel hybrid push-pull protocols for peer-to-peer video streaming. Our approaches intend to reap the best of push- and pull-based schemes by adaptively switching back and forth between the two modes according to video chunk distributions. The efficacy of the proposed protocols is validated through an evaluation study that demonstrates substantial performance gains.

We present a scenario-aware bus functional modeling method which improves the accuracy of traditional methods without sacrificing the simulation run time. Existing methods focused on the behavior of individual IP (Intellectual Property) components and neglected the interplay effects among them, resulting in accuracy degradation from the system perspective. On the other hand, our method thoroughly considers such effects and increases the analysis accuracy by adopting control signal modeling and hierarchical stochastic modeling. Furthermore, our method minimizes the additional design time by reusing the simulation results of each IP component and an automated design flow. The experimental results show that the accuracy of our method is over 90% of RTL simulation in a multimedia SoC (System-on-Chip) design.

This letter presents a new approach to provide inter-domain service compositions for OSGi environments. Our proposal of remote wire objects extends OSGi's wiring capability across the framework boundaries, so that even remote services can join in the composition. Hence, a better composition is made possible with a richer set of candidate services from foreign domains.

In this paper, a new error concealment algorithm for MPEG-4 object-based video is presented. The algorithm consists of a feature matching step to identify temporally corresponding features between video frames and an affine parameter estimation step to find the motion of the feature points. In the feature matching step, an efficient cross-radial search (CRS) method is developed to find the best matching points. In the affine parameter estimation step, a non-iterative least squares estimation algorithm is developed to estimate the affine parameters. An attractive feature of the algorithm is that the shape data and texture data are handled by the same method. Unlike previous methods, this unified approach works for the case where the video object undergoes a drastic movement, such as a sharp turn. Experimental results show that the proposed algorithm performs much better than previous approaches by about 0.3-2.8 dB for shape data and 1.6-5.0 dB for texture data.

Management of applications in the new world of pervasive computing requires new mechanisms to be developed for admission control, QoS negotiation, allocation and scheduling. To solve such resource-allocation and QoS provisioning problems within pervasive and ubiquitous computational environments, distribution and decomposition of the computation are important. In this paper we present a QoS-based welfare economic resource management model that models the actual price-formation process of an economy. We compare our economy-based approach with a mathematical approach we previously proposed. We use the constructs of application benefit functions and resource demand functions to represent the system configuration and to solve the resource allocation problems. Finally empirical studies are conducted to evaluate the performance of our proposed pricing model and to compare it with other approaches such as priority-based scheme and greedy method.

We propose a novel topology control scheme that reduces the transmission power of nodes and increases the network connectivity, based on the fact that Cooperative Communication (CC) technology can bridge disconnected networks. Simulation results demonstrate that our scheme greatly increases the connectivity for a given transmission power, compared to other topology control schemes.

A packet memory stores packets in internet routers and it requires typically RTTC for the buffer space, e.g. several GBytes, where RTT is an average round-trip time of a TCP flow and C is the bandwidth of the router's output link. It is implemented with DRAM parts which are accessed in parallel to achieve required bandwidth. They consume significant power in a router whose scalability is heavily limited by power and heat problems. Previous work shows the packet memory size can be reduced to , where N is the number of long-lived TCP flows. In this paper, we propose a novel packet memory architecture which splits the packet memory into on-chip and off-chip packet memories. We also propose a low-power packet mapping method for this architecture by estimating the latency of packets and mapping packets with small latencies to the on-chip memory. The experimental results show that our proposed architecture and mapping method reduce the dynamic power consumption of the off-chip memory by as much as 94.1% with only 50% of the packet buffer size suggested by the previous work in realistic scenarios.

The current version of IEEE 802.15.4 MAC protocol does not support energy-efficient mobility for the low-power device. In this paper, we propose an energy-efficient sleep mode as part of the IEEE 802.15.4 that can conserve energy by considering mobility of mobile sensor devices. The proposed energy-efficient sleep mode dynamically extends the sleep interval if there is no data to transmit from the device or receive from corresponding nodes.

This paper presents a time amplifier design that improves time resolution using an inverter chain delay in SR latches. Compared with the conventional design, the proposed time amplifier has better characteristics such as higher gain, wide range, and small die size. It is implemented using 0.13 µm standard CMOS technology and the experimental results agree well with the theory.