The changes of temperature, salinity and ocean current in underwater environment, have adverse effects on the communication range of sensors, and make them become temporary failure. These temporarily misbehaving sensors are called dumb nodes. In this paper, an energy-efficient connectivity re-establishment (EECR) scheme is proposed. It can reconstruct the topology of underwater acoustic sensor networks (UASNs) with the existing of dumb nodes. Due to the dynamic of underwater environment, the generation and recovery of dumb nodes also change dynamically, resulting in intermittent interruption of network topology. Therefore, a multi-band transmission mode for dumb nodes is designed firstly. It ensures that the current stored data of dumb nodes can be sent out in time. Subsequently, a connectivity re-establishment scheme of sub-nodes is designed. The topology reconstruction is adaptively implemented by changing the current transmission path. This scheme does't need to arrange the sleep nodes in advance. So it can reduce the message expenses and energy consumption greatly. Simulation results show that the proposed method has better network performance under the same conditions than the classical algorithms named LETC and A1. What's more, our method has a higher network throughput rate when the nodes' dumb behavior has a shorter duration.

Systematic research on electromagnetic compatibility (EMC) in Japan started in 1977 by the establishment of a technical committee on “environmental electromagnetic engineering” named EMCJ, which was founded both in the Institute of Electronics and Communication Engineers or the present IEICE (Institute of Electronics, Information and Communication Engineers) and in the Institute of Electrical Engineers of Japan or the IEEJ. The research activities have been continued as the basic field of interdisciplinary study to harmonize even in the electromagnetic (EM) environment where radio waves provide intolerable EM disturbances to electronic equipment and to that environment itself. The subjects and their outcomes which the EMCJ has dealt with during about 40 years from the EMCJ establishment include the evaluation of EM environment, EMC of electric and electronic equipment, and EMC of biological effects involving bioelectromagnetics and so on. In this paper, the establishment history and structure of the EMCJ are reviewed along with the change in activities, and topics of the technical reports presented at EMCJ meetings from 2006 to 2016 are surveyed. In addition, internationalization and its related campaign are presented in conjunction with the EMCJ research activities, and the status quo of the EMCJ under the IEICE is also discussed along with the prospects.

We present a dynamic key generation method, KeyQ, for establishing shared secret keys in EPCglobal Generation 2 (Gen2) compliant systems. Widespread adoption of Gen2 technologies has increased the need for protecting communications in these systems. The highly constrained resources on Gen2 tags limit the usability of traditional key distribution techniques. Dynamic key generation provides a secure method to protect communications with limited key distribution requirements. Our KeyQ method dynamically generates fresh secret keys based on the Gen2 adaptive Q algorithm. We show that the KeyQ method generates fresh and unique secret keys that cannot be predicted with probability greater than 10-250 when the number of tags exceeds 100.

Security plays an important role in several ZigBee applications such as Smart Energy and medical sensor applications. For a secure communication among ZigBee devices, a secret key should be shared among any two ZigBee devices using the Key Distribution protocol. Recently, Yüksel and Nielson proposed a new Key Distribution protocol for ZigBee addressing the security weaknesses of the original ZigBee Key Distribution protocol. In this letter, it is shown that their protocol is not secure against a key de-synchronization attack, and a security-enhanced Key Distribution protocol is newly proposed and analyzed in terms of security.

The establishment of inter-domain traffic engineered paths is a requisite to accomplishing an end-to-end bandwidth guarantee and end-to-end resource optimization. Though the inter-domain paths must be reliable, it is difficult to compute suitable backup inter-domain paths in advance when the traffic engineering information is not disclosed outside of each domain. This means that the inter-domain path computation must satisfy the severe requirement of path establishment delay, since all inter-domain paths traversing the links in failure need to be computed after the failure occurs. Though several inter-domain path computation schemes have been proposed, their relative characteristics remain unknown. First, this paper classifies the conventional inter-domain path computation schemes into two types, i.e. end-to-end and per-domain schemes, and compares their performances under various traffic loads. Based on results of the comparisons, this paper proposes an adaptive inter-domain path computation scheme that can satisfy the severe requirement of the path establishment delay. In this scheme, the domain sequence from the source node to the destination node is divided into multiple sub-domain sequences according to the traffic load in each domain. The end-to-end path computation scheme is applied to the sub-domain sequences under heavy traffic loads, while the per-domain path computation scheme is applied to those under normal traffic loads. The simulation results show that the proposed scheme can adaptively satisfy the requirement for the path establishment delay while it maintains the optimality of path computation, even if the traffic load applied to each domain changes.

A dynamic routing and wavelength assignment (RWA) algorithm encompassing physical impairment due to Four-Wave Mixing (FWM) is proposed, assuming conventional On-Off-Keying (OOK) modulation format. The FWM effect is one of the most severe physical impairments to be considered for the future photonic networks since the accumulation of FWM crosstalk causes a fatal degradation in the wavelength-routed optical network performance. A novel cost function is introduced based upon an impairment-constraint-based routing (ICBR) approach, taking into account the network utilization resources and the physical impairment due to FWM crosstalk. Simulations results show that the proposed algorithm leads to a more realistic system performance compared to those of related approaches of dynamic RWA that fail to consider physical impairments into the routing scheme.

In this paper, we propose an end-to-end lightpath establishment method in multi-domain WDM networks. In this method, each domain contracts the provision of wavelength-state information and the number of wavelengths provided to neighbor domains. According to the contract, each source node selects the probed wavelengths, which are the candidates for backward wavelength reservation. In order to select wavelengths that are likely to be idle through the multi-domain network, the source node collects wavelength-state information from each destination node and ranks wavelengths for each destination node for giving priority. The source node selects the wavelengths with higher ranks. We propose two rank accounting methods for this purpose. Through simulation experiments, we show that the proposed rank accounting methods with the above contract provide better performance in terms of blocking probability with conventional methods, especially when intra-domain traffic is low. We present the effective number of contract wavelengths. Further, we also extend these rank accounting methods to methods that aggressively collect wavelength-state information from other destination nodes. We show further improvement of performance by the extended rank accounting methods.

Authenticated Key Establishment (AKE) protocols enable two entities, say a client (or a user) and a server, to share common session keys in an authentic way. In this paper, we review the previous AKE protocols, all of which turn out to be insecure, under the following realistic assumptions: (1) High-entropy secrets that should be stored on devices may leak out due to accidents such as bugs or mis-configureations of the system; (2) The size of human-memorable secret, i.e. password, is short enough to memorize, but large enough to avoid on-line exhaustive search; (3) TRM (Tamper-Resistant Modules) used to store secrets are not perfectly free from bugs and mis-configurations; (4) A client remembers only one password, even if he/she communicates with several different servers. Then, we propose a simple leakage-resilient AKE protocol (cf.[41]) which is described as follows: the client keeps one password in mind and stores one secret value on devices, both of which are used to establish an authenticated session key with the server. The advantages of leakage-resilient AKEs to the previous AKEs are that the former is secure against active adversaries under the above-mentioned assumptions and has immunity to the leakage of stored secrets from a client and a server (or servers), respectively. In addition, the advantage of the proposed protocol to is the reduction of memory size of the client's secrets. And we extend our protocol to be possible for updating secret values registered in server(s) or password remembered by a client. Some applications and the formal security proof in the standard model of our protocol are also provided.

Integration of the MPLS network and the optical mesh network is a promising approach to realize an efficient backbone network. Because large volumes of traffic incur damage from failure, survivability is important in the backbone network. In the MPLS over optical networks, a pair of primary LSP (Label Switched Path) and secondary LSP needs to be established on two optical link-disjoint routes assuming all single optical link failures. However, two link-disjoint routes in the MPLS layer may not correspond to two link-disjoint routes in the optical layer. Thus, a pair of primary and secondary LSPs should be routed considering link-disjointness in the optical layer. In the MPLS over optical networks, secondary LSPs can mutually share lightpath bandwidth if those secondary LSPs correspond to the primary LSPs that never fail simultaneously. Thus, routing of secondary LSPs should promote sharing of the lightpath bandwidth among the secondary LSPs. The primary and secondary LSPs with variable bandwidths should efficiently be packed into fewer lightpaths with a fixed bandwidth. Moreover, if all the LSPs accommodated in a lightpath can be re-routed to other lightpaths, this lightpath can then be released. By re-routing only secondary LSPs, unnecessary lightpaths may be released without disturbance of the conveyed traffic. This paper proposes an efficient routing scheme to establish primary and secondary LSPs with variable bandwidths through the MPLS over optical network. This routing scheme satisfies the above conditions. The bandwidth of each lightpath is efficiently utilized by this routing scheme, and the loss rate of LSP requests can be reduced. This paper also proposes an efficient re-routing scheme to remove secondary LSPs from selected lightpaths through which the efficiency of channel utilization in the optical links is increased, and the loss rate of LSP requests can be reduced as a result. Both the proposed routing and re-routing schemes are quantitatively evaluated and the effectiveness of those schemes is verified by computer simulation.

This paper proposes a new distributed connection establishment scheme involving several competing network providers in a multimedia telecommunications environment. This connection establishment scheme, which is based on the concept of open competitive bidding, enables mutual selection by users and network providers. By employing this proposed scheme, both network providers and users can pursue their own objectives, according to their own bidding and awarding strategies. In this paper, a simple bidding strategy for network providers is presented, and the effectiveness of this strategy is evaluated by means of computer simulation. It is shown that each network provider can improve its profit by adopting this strategy. In this paper, an example of utility functions for users is presented, and the effectiveness of the mechanism with which users can select a network provider is also evaluated by means of computer simulation. Each user can improve his/her utility by selecting an appropriate network provider based on this utility function.

In the future, more and more network providers will be established through the introduction of an open telecommunications market. At this time, it is necessary to guarantee the fair competition between these network providers. In this paper, a negotiation protocol for connection establishment is proposed. This negotiation protocol is based on the concept of open, competitive bidding and can guarantee fair competition between the network providers. In this negotiation protocol, each network providers objective is to maximize its profit. Conversely, each users objective is to select a network provider which will supply as much capacity as required. Employing this negotiation protocol, the users and the network providers can select each other based on their objectives. In this paper, adaptation strategies which network providers and users can adopt under the proposed negotiation protocol framework are also discussed. A network provider which adopts this strategy can obtain enough profit even when the number of connection requests is small relative to the idle bandwidth capacity. Moreover, a user who adopts this strategy can be sure to obtain bandwidth even when the idle bandwidth capacity is small relative to the number of connection requests.

Recently as one of attractive applications in the B-ISDN era, LAN/MAN interconnection through an ATM network has been coming up because burstiness of LAN/MAN data traffic is applicable to distinctive features of cell based ATM network. In order to overcome a difference of the connection mode, i.e., CL packet transfer of LAN/MAN and CO cell transfer of ATM network, a number of interworking and bandwidth allocation mechanisms have been proposed. These methods, however, indicate both merits and drawbacks concerning with CL data transfer quality, network resource efficiency and processing overhead in IWU/CLS and the network, and have been mostly evaluated only for a single IWU model. This paper aims at showing the most appropriate method of LAN/MAN interworking for IWU-IWU or IWU-CLSF connection. In the paper, some interworking issues including a general qualitative assessment are clarified. We then evaluate the selected five interworking methods based on Bandwidth Renegotiation (BR) and VC Establishment (VCE), which are combined with Traffic Enforcement Functions (TEFs) based on policing mechanisms and Cell Loss Control (CLC) scheme. By transient and stationary simulation approach for a single IWU and an IWU-CLS connection model, the most applicable method is indicated as a case study from view points of the communication quality, effective use of the bandwidth and processing load.