In the fourth industrial revolution, securing the protection of supply chains has become an ever-growing concern. One such cyber threat is a hardware Trojan (HT), a malicious modification to an IC. HTs are often identified during the hardware manufacturing process but should be removed earlier in the design process. Machine learning-based HT detection in gate-level netlists is an efficient approach to identifying HTs at the early stage. However, feature-based modeling has limitations in terms of discovering an appropriate set of HT features. We thus proposeNHTD-GLin this paper, a novel node-wise HT detection method based on graph learning (GL). Given the formal analysis of the HT features obtained from domain knowledge,NHTD-GLbridges the gap between graph representation learning and feature-based HT detection. The experimental results demonstrate thatNHTD-GLachieves 0.998 detection accuracy and 0.921 F1-score and outperforms state-of-the-art node-wise HT detection methods.NHTD-GLextracts HT features without heuristic feature engineering.

Graph neural networks (GNNs) have been actively employed in hardware security and have demonstrated remarkable performance. In particular, GNN models for hardware Trojan (HT) detection significantly outperform existing machine learning-based detection methods. However, GNNs have a potential vulnerability to membership inference attack (MIA), which aims to determine whether a given sample is used in the training dataset. In this paper, we investigate the threat of MIAs for GNN-based HT detection models. First, the MIA scheme for GNN-based HT detection models is established based on the basic MIA settings. The experimental results demonstrate that MIA for GNN-based HT detection can leak information about the HTs included in the training dataset with a 0.945 attack AUC score in the worst-case scenario. Based on this observation, we propose a defense method against MIA utilizing a domain generalization technique. The proposed defense method successfully mitigated the vulnerability of MIA and degraded the attack AUC score to 0.536 for the netlist level while maintaining the original HT detection performance.

A new state space model suitable for fixed shore net fishing is proposed and successfully applied to daily fish catch forecasting. Accurate prediction of daily fish catches makes it possible to support fishery workers with decision-making for efficient operations. For that purpose, the predictive model should be intuitive to the fishery workers and provide an estimate with a confidence. In the present paper, a fish catch forecasting method is developed using a state space model that emulates the process of fixed shore net fishing. In this method, the parameter estimation and prediction are sequentially performed using the Hamiltonian Monte Carlo method. The experimental comparisons using actual fish catch data and public meteorological information demonstrated that the proposed forecasting system yielded significant reductions in predictive errors over the systems based on decision-trees and legacy state-space models.

This paper describes the development of one DoF robotic hand that makes human laugh by tickling through rubbing underarm. Laughter is attracting research attention because it enhances health by treating or preventing mental diseases. However, laughter has not been used effectively in healthcare because the mechanism of laughter is complicated and is yet to be fully understood. The development of a robot capable of making humans laugh is useful for clarifying the mechanism of laughter because the stimuli by the robot is quantitative and reproductive. Especially, tickling matches to this purpose because the relationship between stimuli and reaction is simpler compared to other techniques. Therefore, this research aimed to develop a robotic hand that can output quantitative and reproductive tickling stimuli for clarifying the mechanism of laughter. Rubbing underarm is selected as a target motion of robot because previous research suggested that this is the best way for making humans feel ticklish. In order to achieve the tickling motion by robots as humans, the required specifications were determined through experimental method. In order to develop a robot that achieves the required fingertip trajectory by simple mechanisms as much as possible, mechanism with crank and link driven by single motor was developed. The result of experimental evaluation shows that the developed robot could make humans laugh by its rubbing motion. In addition, the quantitative tickling motion by developed robotic hand was suggested to be effective for clarifying the mechanism of laughter.

This paper describes the development of a robotic head that has cartoon facial expression ability with comic marks. For communicating with humans, robots should have expressive facial expression ability for indicating their inner state. Our previous research suggests that robots can express its emotion clearly if it performs facial expressions that are adapted to the cultural background of the communication partner. As a first step, we focus on making expressions for Japanese people. Comic mark is a unique and famous way of emotion expression in Japanese culture. First, we defined facial expressions by combining cartoon-like shape of the facial parts with high emotion recognition rates. Then we asked cartoonists to draw comic marks which they think are effective for emotion expression and find the effective comic marks as “Cross popping veins” for “Anger”, “Tear mark” for “Sadness” and “Vertical lines” for “Fear”. Finally we obtained a model expression which has sufficiently high emotion recognition rate from the combination of the facial expression and the comic marks. In order to achieve these expressions, we developed flexible full color LED display matrix module and mechanism that push and pull the sheet for expressing black lines. Results of experimental evaluation shows that the new robotic head has over 90% average emotion recognition rates for each of the six basic emotions. The results with non-Japanese subjects suggests that impression of emotion expression on robotic head changes depending on the cultural background. These findings encourage us in pursuing this concept of designing robots that display emotions that are adapted to cultural background of communication partner.

Japan, along with many developed countries, is facing severe social problems caused by a declining birth rate. Gradual shrinkage of the working population has brought shortages of workers performing various services such as elderly care. Women are potential workers, but social assistance of working women remains insufficient. Social services such as elderly care and support for working women must be developed to address these problems. The infrastructure for future ubiquitous services must be designed as a service platform to provide those services respecting individual personal circumstances and at socially acceptable cost. Ubiquitous services provide enhanced mobility. Future ubiquitous services will evolve toward enhanced pervasiveness, and will be defined as advanced personalized services. This report presents a new concept, Socio-familiar Personalized Service (S-P Service), for future ubiquitous services based on sociality and humanity. Moreover, we propose a scalable distributed authentication method to realize S-P Service.

IP multicasting is an efficient and scalable way to deliver high quality audio and video streams for group communication. However, widespread deployment of IP multicast is unlikely in near future and it requires substantial infrastructure modifications. For rapid deployment of multicast application, Application Layer Multicast (ALM) is an alternate choice to circumvent this situation, as it supports group communication independent of network layer support. Previous studies on ALM mainly focused on achieving high throughput for bandwidth intensive applications and unfairness of communication quality is still a serious issue in multi-source communication. In this paper, we present an autonomous distributed scheme to construct an ALM tree to improve fairness and overall communication quality among the participants in a multi-source multimedia communication. Extensive simulation and experimental results show that our proposed scheme increases the incoming bitrate of the lowest recipient among all the nodes, as well as improving fairness for all receivers.

In ubiquitous environments, there are a huge number of computer nodes which provide a lot of information services via the Internet. Therefore, a secure communication system is required for ubiquitous environments. In this paper, we propose a new architecture of distributed public key infrastructure, named as Hash-based Distributed Public Key Infrastructure (HDPKI). A HDPKI system achieves a scalable management of public key certificates by using Distributed Hash Table. Additionally, it is easy to use a HDPKI system, because we can register our public key certificates automatically. In this paper, we show scalability of HDPKI through computer simulation. According to these results, the total amount of required messages for certificate management in a HDPKI system is O(log n) where n is the number of nodes.

The Wireless Mesh Network (WMN) has already been recognized as a promising technology as broadband access network from both academic and industry points of view. In order to improve its performance, research has been carried on how to increase the number of simultaneous transmissions in the network while avoiding signal interference among radios. Considering WMNs based upon IEEE 802.11 b/g standards, lately most of researchers have been relying on the usage of orthogonal channels for solving the Channel Assignment (CA) problem. However, in this paper, we introduce a novel CA algorithm exploiting partially overlapped channels (POC) that overcome the common orthogonal channel approach and also a recent proposed CA algorithm using POC.

Scalability is one of the main challenges for kernel-based methods and support vector machines (SVMs). The quadratic demand in memory for storing kernel matrices makes it impossible for training on million-size data. Sophisticated decomposition algorithms have been proposed to efficiently train SVMs using only important examples, which ideally are the final support vectors (SVs). However, the ability of the decomposition method is limited to large-scale applications where the number of SVs is still too large for a computer's capacity. From another perspective, the large number of SVs slows down SVMs in the testing phase, making it impractical for many applications. In this paper, we introduce the integration of a vector combination scheme to simplify the SVM solution into an incremental working set selection for SVM training. The main objective of the integration is to maintain a minimal number of final SVs, bringing a minimum resource demand and faster training time. Consequently, the learning machines are more compact and run faster thanks to the small number of vectors included in their solution. Experimental results on large benchmark datasets shows that the proposed condensed SVMs achieve both training and testing efficiency while maintaining a generalization ability equivalent to that of normal SVMs.

DNS is one of the internet's fundamental building blocks, used by various applications such as web and mail transfer. Therefore, monitoring DNS traffic has potential to detect host anomalies such as spammers and infected hosts in a network. However, previous works assume a small number of hosts or target on domain name anomalies, so that they cannot be applied to a large-scale networks due to performance issues. A large number of hosts and long-term tracing consume computational resources and make real-time analysis difficult. In this paper, we propose anomaly detection for DNS servers using frequent host selection, which selects only potential hosts and does not depend on the number of hosts. We evaluate the proposed system using DNS traffic for 6 months of tracing, and show that the system can feasibly handle hosts in the dataset and detect anomalies, such as mail servers suffering from spam and DNS servers are configured incorrectly.

Access control to resources is one of the most important technologies for supporting human activities in the digital space. To realize control two schemes were proposed: RBAC (role-based access control) and TRBAC (temporal role-based access control) by adding time constraints and role dependencies to RBAC. However, these methods are not effective for temporal activities because of maintenance costs and inadequacy in safeness. In this paper, we focus on a flexible and secure access control in the real space, by using relations with users and situations, and propose a novel access control which is effective for temporal activities.

Due to the dynamic topology and non infrastructure, network participants cooperate with their neighbors to route packets. The lack of centralized services allows mobile ad hoc networks to be easily and swiftly deployed, but make it difficult to check others' identities on the other hand. Cryptographic tools have been introduced to secure group communications, such as private and public key infrastructure. The autonomous and distributed nature of mobile ad hoc network demands a decentralized authentication service, where public key infrastructure is considered a better solution. Public key infrastructure can ensure both confidentiality and authenticity, but it is impractical to provide an online trusted third party as certificate authority (CA) for mobile ad hoc network. In this paper, we proposed a new key management protocol which utilizes certificate graphs and distributed certificate authorities. Certificate graph maintained by each user represents the trust among his neighbors, then the maximum clique of certificate graph is selected to be CAs. Based on the assumption that initial certificate graph building is secure, good users have more friends while bad ones have less, thus a reliable group can be constructed. The most trustful subset of these good users -the maximum clique - is elected as the governor of this group, which takes the responsibility of certificate authentication.

Despite recent advances in networking technologies, video streaming applications still suffer from limited bandwidth and highly varying network conditions. As a solution, this paper proposes a novel multi-source streaming strategy specifically tailored for next generation mobile networks to deliver multimedia services to mobile users. The proposed solution consists of a set of mechanisms that aim at ensuring seamless, continuous, and smooth playback of video for users, guaranteeing an efficient and fair utilization of network resources while meeting the playback and buffer constraints of the clients, preventing redundant transmissions and minimizing packet reordering. A set of computer simulations is conducted to evaluate the performance of the proposed strategy and encouraging results are obtained.

Video streaming to mobile users is gaining momentum within the communities of both industrial and academic researchers. In a previous research work, the authors proposed a multi-source streaming method for video streaming to mobile users. The focus was on video fragmentation and packet scheduling to avoid packet reordering and packet redundancy. As a continuation to the work, this paper presents a handoff management method to support userspsila mobility and to guarantee continuous and smooth playback of video data for users while they are on move. For performance evaluation, some simulation results are presented.

In this paper, we develop an efficient vehicle collision avoidance strategy for intelligent transport systems. The proposed strategy first clusters vehicles according to the features of their movement (e.g., direction of movement, inter-vehicle distance, and relative velocity). To enhance the responsiveness of the proposed CCA system, a risk-aware MAC protocol is designed. In the proposed scheme, an emergency level is defined for each vehicle based on its order in its respective cluster. The emergency level reflects the risk of a vehicle to meet an emergency situation in the platoon. The medium access delay of each vehicle is set as a function of its emergency level in a way that enables vehicles in emergency situations to promptly disseminate warning messages to neighboring vehicles and to accordingly minimize chain collisions. The proposed CCA system is dubbed cluster- based risk-aware CCA (C-RACCA). The performance of the proposed C-RACCA system is evaluated via simulations and encouraging results are obtained.

In multi-hop sensor networks, information obtained by the monitoring nodes need to be routed to the sinks. If we assume that the transmitter power level can be adjusted to use the minimum energy required to reach the intended next hop receiver, the energy consumption rate per unit information transmission depends on the choice of the next hop node. In a power-aware routing approach, most proposed algorithms aim at minimizing the total energy consumption or maximizing network lifetime. In this paper, we propose a new routing algorithm with two goals: minimizing the total energy consumption and ensuring fairness of energy consumption between nodes. We formulate this as a nonlinear programming problem and use a sub-gradient algorithm to solve the problem. We also evaluate the proposed algorithm via simulations at the end of this paper.

This paper presents a novel scheme that enables IPv6 mobile networks to perform optimal route optimization. The proposed scheme exploits features of the widely deployed border gateway protocol (BGP). When a mobile network is about to change its point of attachment to the Internet, its mobile router (MR) gets a new care-of-address (CoA) from the visited location and sends a binding update to its home agent (HA). Additionally, MR gets a new temporary network prefix (TNP) at the new location using the prefix delegation protocol. MR then advertises this TNP to its subnet via a router advertisement (RA) message and enables the mobile network nodes (MNNs) to build their own respective CoAs. Simultaneously, this TNP is also sent to the border router (BR) of the home network to enable BR update its BGP routing table. This operation is performed to build an association between the TNP and the mobile network prefix (MNP). BR then notifies its peers of this new update. This procedure will enable any correspondent node (CN) to directly communicate with MNNs, avoiding therefore ingress filtering and reducing both signaling and processing overhead on MR and the home agent (HA). A comparison of the proposed scheme against the NEMO Basic Support scheme, in terms of communication delay, is made via a simple performance analysis.

The transmission of high quality video requires high bandwidth. Ensuring constantly high bandwidth in wireless environments is a challenging task given constraints in the current wireless network resources. Current mobile computers are equipped with multiples wireless interfaces that can be used to improve the video quality by aggregating the bandwidth of these interfaces. Such Bandwidth Aggregation (BAG) approach involves multiple paths in communication and gives rise to a number of issues related to the management of the Service Level Agreement (SLA) and packet reordering. To guarantee an efficient and fair management of SLA, this paper presents a bandwidth aggregation-aware QoS negotiation mechanism that enables users to dynamically negotiate their desired service levels and to reach them through the use of bandwidth aggregation. This operation is performed while ensuring a fair use of the network resources among all competing users. To cope with packet reordering, a new scheduling strategy is presented. The performance evaluation of the proposed bandwidth aggregation-aware QoS negotiation scheme and the proposed scheduling algorithm are conducted via simulations and the results are discussed.

Attacks against encrypted protocols are becoming increasingly popular. They pose a serious challenge to the conventional intrusion detection systems (IDSs) which heavily rely on inspecting the network packet fields and are consequently unable to monitor encrypted sessions. IDSs can be broadly categorized into two types: signature-based and anomaly-based IDSs. The signature-based IDSs rely on previous attack signatures but are often ineffective against new attacks. On the other hand, anomaly-based detection systems depend on detecting the change in the protocol behavior caused by an attack. The latter can be employed to detect novel attacks, and therefore are often preferred over their signature-based counterpart. In this paper, we envision an anomaly-based IDS which can detect attacks against popular encrypted protocols, such as SSH and SSL. The proposed system creates a normal behavior profile and uses non-parametric Cusum algorithm to detect deviation from the normal profile. Upon detecting an anomaly, the proposed mechanism generates an alert, sets a delay to the protocol response, and traces back the attacker. The effectiveness of the proposed detection scheme is verified via simulations.

Satellite communication systems exhibit important and unique features that qualify them to be an integral part of a global ubiquitous information system. Given the universality of the Internet protocol (IP), traffic over satellite network is expected to be all IP. Success of these all-IP satellite systems depends on their abilities to guarantee QoS. QoS provisioning has been a hot topic in terrestrial wired networks. It has been, however, highly overlooked in wireless networks. An efficient QoS provisioning in wireless networks in general, and in satellite networks in particular, can be possible only with the development of new schemes that are able to dynamically (re)negotiate service levels in an adaptive manner to changes in network conditions upon handoff occurrences. This paper surveys major dynamic service level negotiation schemes proposed for terrestrial wireless networks and discusses their limitations when applied to satellite networks. As a solution, a dynamic service level negotiation scheme specifically tailored to satellite networks is portrayed. Comparison of the proposed scheme to other dynamic negotiation approaches, via a qualitative and quantitative analysis, is also presented.

Mobile users are expected to be highly dynamic in next generation mobile networks. Additionally they will be served a wide variety of services with different transmission rates and expect high quality of service (QoS). Since the number of mobile subscribers is rapidly increasing and given the limited resources of any robust network, guarantee of high QoS is possible only by the deployment of network elements that optimally allocate network resources and instantly adapt to network conditions. In attempt to support mobility in IP networks, the hierarchical mobile IPv6 (HMIPv6) has been proposed. An important issue that has been highly overlooked in the design of HMIPv6 consists in its lack of a mechanism that can efficiently control and distribute traffic among multiple mobility anchor points (MAPs). In the absence of such mechanism, some MAPs may get congested while others remain underutilized. In such scenario, mobile users connecting to congested MAPs may experience significant packet drops and excessive queuing delays. This ultimately affects QoS. In this vein, this paper proposes an application-driven mechanism for selection of MAPs. The key idea behind the proposed scheme consists in the reference of access points to the transmission rate of the users' applications to decide which MAP visiting users should be registering with. The decision of MAPs is performed in a way that the load variance of all MAPs, serving the access point in question, is minimized. Issues related to the frequency of binding update messages are also considered in the selection of MAPs. The performance of the proposed scheme is evaluated via computer simulations. In terms of QoS, encouraging results are obtained: better traffic distribution among MAPs and lower handoff delays.

Attacks against encrypted protocols have become increasingly popular and sophisticated. Such attacks are often undetectable by the traditional Intrusion Detection Systems (IDSs). Additionally, the encrypted attack-traffic makes tracing the source of the attack substantially more difficult. In this paper, we address these issues and devise a mechanism to trace back attackers against encrypted protocols. In our efforts to combat attacks against cryptographic protocols, we have integrated a traceback mechanism at the monitoring stubs (MSs), which were introduced in one of our previous works. While we previously focused on strategically placing monitoring stubs to detect attacks against encrypted protocols, in this work we aim at equipping MSs with a traceback feature. In our approach, when a given MS detects an attack, it starts tracing back to the root of the attack. The traceback mechanism relies on monitoring the extracted features at different MSs, i.e., in different points of the target network. At each MS, the monitored features over time provide a pattern which is compared or correlated with the monitored patterns at the neighboring MSs. A high correlation value in the patterns observed by two adjacent MSs indicates that the attack traffic propagated through the network elements covered by these MSs. Based on these correlation values and a prior knowledge of the network topology, the system can then construct a path back to the attacking hosts. The effectiveness of the proposed traceback scheme is verified by simulations.

Users in next generation wireless networks are expected to be highly dynamic while maintaining connectivity through different devices with different processing and communication capabilities. In wireless environments, bandwidth is scarce and channel conditions are time-varying. To guarantee quality of service (QoS) to users roaming between heterogeneous wireless networks, a dynamic QoS negotiation mechanism, which allows users to dynamically negotiate their service-levels with the network, is required. Several protocols for dynamic service level negotiation have been proposed, each focusing on a particular mode. This paper presents an overview of these protocols and discusses their limitations. To alleviate these shortcomings, a dynamic QoS negotiation scheme to allow users to change their service levels in response to changes in both network conditions and their own resource requirements is proposed. In the proposed scheme, upon an intra-domain handoff of a mobile node, the visited access point consults the previously used access point to confirm the legitimacy of the service negotiation request issued by the mobile node. The performance of the proposed scheme has been investigated and compared with other dynamic negotiation approaches. It was demonstrated that the proposed scheme outperforms the state-of-the-art method, in terms of the signaling overhead and data storage, at the expense of a slight increase in the overall negotiation delay.

In light of the fast propagation of recent Internet worms, human intervention in securing the Internet during worm outbreaks is of little significance. In order to reduce the damage worms may cause, existing intrusion detection systems (IDSs) need to be adaptive to the security-related requirements of their monitoring networks. This paper presents a Multilevel security based Autonomic Parameter Selector (MAPS) that can be implemented over any existing IDSs. The deployment architecture consists of a number of hierarchically placed local security managers, metropolitan security managers, and a global security manager. These security managers report events to a worm advisory system (WAS). WAS accordingly sets the threat level of the network. Based on this level, MAPS selects the most optimum parameters for the entire IDS to combat against the propagating worm. The MAPS architecture maintains the system performance by constantly evaluating three metrics, namely False Negative Avoidance, False Positive Avoidance, and performance overhead. Extensive experiments, using real network traffic and a recently proposed worm detection system, demonstrate that MAPS is capable of advising an IDS with optimum parameter values to effectively and promptly hinder further propagation of worms.

Due to geographical and/or climatic constraints, the community of future satellite users will exhibit a significant variance in its density over the Globe. This density variance will yield a scenario where some satellite links are congested while others are underutilized. To ensure an intelligent engineering of traffic over satellite networks, this paper proposes a routing protocol that enables neighboring satellites to explicitly exchange information on their congestion status. A "soon-to-be-congested" satellite requests its neighboring satellites to decrease their data forwarding rates. In response, the neighboring satellites search for less congested paths that do not include the satellite in question and communicate a portion of data, primarily destined to the satellite, via the retrieved paths. By so doing, congestion, and the resulting packet drops, can be avoided. A better distribution of traffic among satellites can be guaranteed as well. The proposed scheme is dubbed "Explicit Load Balancing" (ELB) scheme. A set of simulations is conducted to evaluate the performance of the ELB scheme using the Network Simulator. In terms of Quality of Service, encouraging results are obtained: better traffic distribution, higher throughput, and lower packet drops.

This paper describes the architecture of a global sensor network based on a constellation of LEO satellites. The considered sensor network is heterogeneous: two types of sensor nodes are envisioned. One type does the sensing and relays the gathered data to the other type that performs data aggregation and communicates it directly to the satellites. The main challenging tasks in the design of the architecture are explored and adequate solutions are provided. A set of data dissemination techniques is then presented. Following this, a mathematical model is developed to evaluate the energy use of the sensors. Open research issues for the realization of such architecture are finally discussed.

Multimedia contents transmission and management system "VAST-web" is proposed. It employs store-and-forward transmission technique to maintain the contents quality. It also has a central management function of contents stored at remote locations so that contents query and contents pull model as well as contents push model are supported. A novel transmission protocol "SVFTP" is also introduced, which is a core technique in VAST-web. Its throughput performance is evaluated theoretically and experimentally to show it is well-suited to large volume multimedia contents transmission. Besides, its pipeline transmission capability provides VAST-web system with great flexibility for media playback.

No abstract available.

Document filtering is a task to retrieve documents relevant to a user's profile from a flow of documents. Generally, filtering systems calculate the similarity between the profile and each incoming document, and retrieve documents with similarity higher than a threshold. However, many systems set a relatively high threshold to reduce retrieval of non-relevant documents, which results in the ignorance of many relevant documents. In this paper, we propose the use of a non-relevant information profile to reduce the mistaken retrieval of non-relevant documents. Results from experiments show that this filter has successfully rejected a sufficient number of non-relevant documents, resulting in an improvement of filtering performance.