Intergenerational co-design often assumes a Western democratic ideal of flattened hierarchies. Engaging with pluriversal design perspectives, this paper challenges these universalist assumptions by investigating extrafamilial co-design in a non-Western context shaped by Confucian values. We explore how unrelated older adults and teenagers negotiate authority within high-power-distance environments, using Virtual Reality as a "social disruptor" to redistribute expertise. We propose a taxonomy of four interaction modes-Unilateral Transmission, Benevolent Authority, Material Authority, and Synthesized Co-Creation-to describe how power is fluidly negotiated. Our findings reveal that design tools function as "political shields," allowing youth to assert agency while maintaining cultural harmony. We contribute a micro-analysis of power-asymmetric collaboration and provide workshop strategies designed for functional reciprocity. The rationale for these strategies is to navigate, rather than dismantle, rigid social structures, providing actionable insights for practitioners working in diverse, culturally situated design environments.

This study investigates how Southeast Asian (SEA) immigrant mothers in Taiwan participate in their children’s home-based learning. Drawing on semi-structured interviews and diary studies, we explore how these mothers navigate sociocultural constraints while fostering engagement and transmitting cultural values. Despite facing diminished agency and structural marginalization, mothers engage creatively in their children’s everyday learning interactions. Guided by a justice-oriented lens, we identify various harms and propose design implications for socio-technical systems that center recognition, reciprocity, and accountability in parent-child learning at the individual, familial, and societal levels. Our contribution lies in foregrounding the role of intersectional identity in parent-child learning and proposing justice-oriented design directions that support the flourishing of immigrant mothers within socio-technical systems.

This study examines the intersection of academic pressure and sleep within Taiwanese families, revealing how cultural norms and expectations shape sleep practices. Through interviews and two-week diaries from eleven families, we found that academic demands significantly influence children's sleep patterns, leading to reduced sleep duration and varied sleep schedules. Our research highlights the importance of integrating care and attuning into the design of sleep-tracking technologies, advocating for a family informatics approach that considers both health needs and social expectations. By exploring these dynamics, we contribute to a broader understanding of family contexts in diverse cultural settings and offer insights for more inclusive technology design.

Due to the scarcity of training samples, Few-Shot Learning (FSL) poses a significant challenge to capture discriminative object features effectively. The combination of transfer learning and meta-learning has recently been explored by pre-training the backbone features using labeled base data and subsequently fine-tuning the model with target data. However, existing meta-learning methods, which use embedding networks, suffer from scaling limitations when dealing with a few labeled samples, resulting in suboptimal results. Inspired by the latest advances in FSL, we further advance the approach of fine-tuning a pre-trained architecture by a strengthened hierarchical feature representation. The technical contributions of this work include: 1) a hybrid design named Intra-Block Fusion (IBF) to strengthen the extracted features within each convolution block; and 2) a novel Cross-Scale Attention (CSA) module to mitigate the scaling inconsistencies arising from the limited training samples, especially for cross-domain tasks. We conducted comprehensive evaluations on standard benchmarks, including three in-domain tasks (miniImageNet, CIFAR-FS, and FC100), as well as two cross-domain tasks (CDFSL and Meta-Dataset). The results have improved significantly over existing state-of-the-art approaches on all benchmark datasets. In particular, the FSL performance on the in-domain FC100 dataset is more than three points better than the latest PMF (Hu et al. 2022).

Few-Shot Learning (FSL) has attracted growing attention in computer vision due to its capability in model training without the need for excessive data. FSL is challenging because the training and testing categories (the base vs. novel sets) can be largely diversified. Conventional transfer-based solutions that aim to transfer knowledge learned from large labeled training sets to target testing sets are limited, as critical adverse impacts of the shift in task distribution are not adequately addressed. In this paper, we extend the solution of transfer-based methods by incorporating the concept of metric-learning and channel attention. To better exploit the feature representations extracted by the feature backbone, we propose Class-Specific Channel Attention (CSCA) module, which learns to highlight the discriminative channels in each class by assigning each class one CSCA weight vector. Unlike general attention modules designed to learn globalclass features, the CSCA module aims to learn local and class-specific features with very effective computation. We evaluated the performance of the CSCA module on standard benchmarks including miniImagenet, Tiered-ImageNet, CIFAR-FS, and CUB-200-2011. Experiments are performed in inductive and in/cross-domain settings. We achieve new state-of-the-art results.

This study delves into the digital interactions of stay-at-home moms (SAHMs) in Taiwan, exploring their utilization of LINE messaging app's chat groups as a pivotal means for informational, emotional, and practical support amidst their parenting journeys. Amidst the dominant patriarchal societal norms and potential isolations intrinsic to their role, these SAHMs establish a robust, cooperative digital environment, wherein maternal experiences, knowledge, and emotional backings are collectively shared and curated. Through a two-stage interview study, employing chatbot technology over 14 days with 18 participants, we unveiled how SAHMs engage in both tacit and explicit collaborative work within these chat groups, reclaiming their maternal identity and amplifying their parenting confidence. This exploration not only illuminates the critical role of technology in enhancing collaborative maternal work but also propels the discourse on how SAHMs navigate their distinctive needs within specific socio-cultural contexts through technological means. Consequently, this offers a foundational perspective towards crafting technological designs that are empathetically attuned to the lived experiences and needs of SAHMs in Taiwan.

Mobile users commonly multitask during travel, but doing so on public transit can be challenging due to the dynamic nature of the environment as well as long-standing lack of infrastructural support. Nevertheless, HCI scholars and practitioners have devoted relatively little attention to developing technology for enhancing travel multitasking. To facilitate such development, we sought to understand travel multitaskers’ practices and challenges while on public transit, and to that end, conducted a multi-methods study that involved shadowing and interviewing 30 of them. We identified four travel-multitasking patterns, characterized by distinct motives that affected these travelers’ multitasking practices, receptivity to environmental stimuli, and task persistence. The two main challenges they encountered during travel multitasking resulted from mutual interference from their tasks and from the dynamic nature of transit environments. Based on these findings, design recommendations for public-transit agencies and mobile services are also provided.

The FMCW radar has lots of advantages such as compact, energy effective and low cost. It is suitable for mounting on the vehicle and also on small sized UAV. In this paper, the high squint angle effect is considered for both the FMCW synthetic aperture radar (SAR) and the inverse synthetic aperture radar (ISAR) in the case of the high resolution vehicle radar. The 2ndrange compression is performed for removing the range and the azimuth coupling effect under the high squint angle situation. The polar reformatting is performed for improving the radar resolution in the ISAR. By keeping practical situation in mind, the image qualities under the squint angle with random error is investigated. In addition, the simulation software for the SAR and the ISAR are developed.

In this workshop, we intend to bring scholars and practitioners of MobileHCI conference who are interested in designing technology use for children and their parents. Parents are concerned with technology addiction for their children but generally feel loss of control in the ubiquity of mobile devices. We believe mobile design community can contribute meaningful ideas in this space. The goal of this workshop is for participants to co-develop a shared vocabulary and framework for "designing bounded and nuanced technology" as a strategy to be deployed in conceiving and implementing mobile technologies for family use.

We present an evaluation of three prototype tangible user interfaces (TUIs) for mealtimes for preschoolers. Building on past work identifying value tensions between adults' and children's perspectives at meals, we evaluated TUIs to address different tensions in this context (for example, the tension between children's interest in experimenting with food versus adults' interest in cleanliness). Thirteen pre-school children and their parents tried out the prototypes, as did an additional seven preschool teachers. Adults and children alike were excited by the prototypes; parents were surprised by children's increased food intake, and children used the prototypes to engage in artistic expression with food traces. However, children's increased consumption was extrinsically motivated by the prototypes rather than intrinsically motivated by hunger. We conclude that TUIs have the potential to enhance shared meals between children and adults but also have the potential to distract or persuade children in inappropriate ways. We present design guidance differentiating these two outcomes, such as incorporating the TUI into pre-existing mealtime objects and routines.

Most technology designed for young children at mealtime centers around conceptions of how the child should eat or behave at the table. Expanding this view to include children's perspectives, we present a two-part study to explore the design of technology for mealtimes in preschools. We first worked to identify existing value tensions through interviews and observations, then designed three prototypes to address different value tensions (e.g., the tension between children's interest in experimenting with food versus the teachers' interest in cleanliness). Although there are specific ways adults' and children's values are in conflict, our work suggests the potential for novel designs to provide creative and meaningful experiences such as playful productivity that support the needs of both parties.

Global app marketplaces make families in foreign countries easily accessible to developers, but most scholarship on joint media engagement (JME) between parents and children reports on data from participants in Western contexts. We conducted an observational lab study to examine how preschoolers (age 3-5) and parents (N=74) from three different regions of the world (communities in China, Taiwan, and the United States) engage with two types of tablet games: an instructional game with goals and an exploratory, open-ended game. We found systematic differences among groups and between games. For example, parents from China and Taiwan frequently picked up their child's hand and used it as a tool to engage with the screen, a practice parents in our U.S. sample did not employ. Dyads from all three samples exhibited more warmth when playing an instructional game than an exploratory one. Our results suggest that characteristics of the populations we sampled interact with design features, that is, the same design prompted opposing behaviors in different groups. We conclude that it may be useful to examine goal-free and goal-oriented JME as separate constructs, that design choices influence the roles parents adopt during JME, and that the range of behaviors we observed complicate the prevailing research narrative of what positive and productive JME looks like.

In this paper, a compact SPICE model of flexible transition metal dichalcogenide field-effect transistors (TMDFETs) is developed with considering effects when scaling the transistor size down to the 10-nm technology node. The model supports different transistor design parameters such as width, length, oxide thickness, and various channel materials, as well as the applied strain, which enables the evaluation of transistor- and circuit-level behavior under process variation and different levels of bending. Extensive device-level simulations are performed using this model, and TMDFETs are compared with different Si- and graphene-based devices. We performed circuit-level simulations, and reported the delay, power, and EDP of the benchmark circuits. Effects from process variation are also evaluated. These cross-technology studies show that TMDFET's power is comparable to the low-power multigate devices (about 0.4% lower). The delay and EDP are 60% and 2.3% higher than the graphene-based devices, respectively. The developed compact model would enable SPICE-level circuit simulation for early assessment, design, and evaluation of futuristic TMDFET-based flexible circuits targeting advanced technology nodes.

In this paper, a new and efficient SPICE model of flexible transition metal dichalcogenide field-effect transistors (TMDFETs) is developed for different types of materials, considering effects when scaling the transistor size down to the 16-nm technology node. Extensive circuit-level simulations are performed using this model, and the delay and power performance of TMDFET circuits with different amounts of bending are reported. Simulation results indicate that delay and power tradeoff can be done in TMDFET circuits via bending. Effects from process variation are also evaluated via circuit simulations. Finally, our cross-technology and scaling studies show that while TMDFETs perform better than Si-based transistors in terms of energy-delay product (EDP) at 180-nm and 90-nm technology nodes (the best being 12.7% and 40.7% of that of Si-based transistors, respectively), their EDPs are worse than Si-based transistors (at least 4.9× of that of the best performing Si-based transistor) on the 16-nm technology node. Such a compact model would enable SPICE-level circuit simulation for early assessment, design, and evaluation of futuristic TMDFET-based flexible circuits targeting advanced technology nodes.

This paper presents an accurate analytical compact model for Schottky-barrier-type graphene nanoribbon field-effect transistors (SB-GNRFETs). This is a physics-based analytical model for the current-voltage (I-V) characteristics of SB-GNRFETs. The proposed model considers various design parameters and process variation effects, including graphene-specific line-edge roughness, which allows thorough exploration and evaluation of SB-GNRFET circuits. We develop accurate approximations of SB tunneling, channel charge, and current, which provide accurate results while maintaining model compactness. We evaluate the effect of design parameters and process variations on the performance of SB-GNRFETs. We also compare circuit-level performance of SB-GNRFETs with multigate (MG) Si-CMOS (e.g., FinFETs). Our circuit simulations indicate that SB-GNRFET has an energy-delay product (EDP) advantage over Si-CMOS, although GNR-specific process variation, especially the line-edge roughness, would significantly downgrade such an advantage; the EDP of the ideal SB-GNRFET (assuming no process variation) is ~2.5% of that of Si-CMOS, while the EDP of the nonideal case with process variation is ~68% of that of Si-CMOS. Finally, we study technology scaling with SB-GNRFET and MG Si-CMOS. We show that the EDP of ideal (nonideal) SB-GNRFET is ~0.88% (54%) EDP of that of Si-CMOS as the technology nodes scale down to 7 nm.

In the common implementation of software defined networking where only one controller is used, tasks required by various applications may overwhelm the controller as the network grows, leading to degradation of the network performance. Some multi-controller architectures have been proposed to remedy such scalability issue. In this paper, we present our design and implementation of a routing application under a hierarchical multi-controller architecture. In this architecture, a network is partitioned into multiple domains, each of which is managed by a dedicated local controller, which is managed by a common global controller. The routing application is executed on the local and global controllers, jointly providing a routing service for each new flow. We provide effective mechanisms to reduce the link state that should be kept by the global controller. We propose a weight function on the links so that a weighted shortest path can be found that avoids the congested links on the network. Experiments results show that our routing application in the hierarchical multi-controller architecture has a great improvement over that of the single-controller architecture in terms various performance metrics.

Over the past decade, the mobile phonebook has evolved from a relatively short list of people that one calls and texts to a many-hundred person list of aggregated contacts from around the web. This is happening at a time when an increasing number of mobile applications are relying on the mobile phonebook to create one's social network in their services. Through a large-scale study of the phonebooks of 200 diverse participants, containing 65,940 contacts, we set out to understand today's mobile contact lists. Our participants reported that they did not recognize the names of 29% of their contacts and we found that the most frequently contacted five contacts represent greater than 80% of all calls and text messages with phonebook contacts. We conclude with implications for the design of mobile applications that rely on phonebook data.

We explore the everyday use of a new abstraction for mo-bile location-sharing. By sharing the travel time between contacts calculated for walking, transit, and driving, we have enabled users to more easily coordinate meeting up and planning family obligations. Specifically, our participants reported that the information helped to lower the stress of these activities and provided reassurance of the arrival times of their close friends and family. In this paper, we describe our system, motivate its design, and explore results from a 20-user, 21-day field trial showing the use-fulness of the abstraction as well as attitudes towards privacy when sharing travel times with close friends or family.

This paper presents the first SPICE model of the transition metal dichalcogenide (TMD) field-effect transistor (FET), which is a promising candidate for flexible electronics. The model supports different transistor design parameters such as width, length, oxide thickness, and various channel materials (MoS2, WSe2, etc.), as well as the applied strain, which enables the evaluation of transistor- and circuit-level behavior under process variation and different levels of bending. We performed SPICE simulations on digital logic gates to explore the design space of both MoS2- and WSe2-based transistors, and to evaluate the projected performance of these circuits under applied strain. Our simulations show that WSe2 circuits outperform MoS2 and Si-based CMOS in terms of energy-delay product (EDP) by 1 order of magnitude or more, depending on applications. Finally, we investigate TMDFET's behavior under process variation.

Today's smartphones enable rich, media-enhanced conversations. Millions of photos and billions of messages are shared each day on smartphones. But how, exactly, are images and web links being used in mobile conversations? And what does this mean for the design of new mobile communications applications? We set out to learn how people currently share and discuss mobile media by performing a detailed content analysis of 109 photos and links that were shared in 2,779 messages using a mobile messaging application deployed in the United State and Taiwan. Through our analysis of these conversations, we show how mobile media is used to experience the moment together, to fill in the visual details, to provide background context, and to exchange information. We then discuss our results and provide two designs inspired by our findings.

This paper focuses on channel assignment in wireless mesh networks. Since nodes have only a limited number of radio interfaces, channel assignment must ensure that the interface constraint is obeyed. Although many channel assignment heuristics have been proposed, the interface constraint is usually treated as a separate constraint that is not well incorporated in the heuristics themselves. In this paper, we propose a mixed hypergraph model that captures the interface constraint on nodes and the interference between links. We propose a greedy-based channel assignment algorithm that minimizes the interference between links while conforming to the interface constraint. Simulation results show that our proposed algorithm performs especially well when the number of network interface cards is small.

In this paper, we present a highly accurate closed-form compact model for Schottky-Barrier-type Graphene Nano-Ribbon Field-Effect Transistors (SB-GNRFETs). This is a physics-based analytical model for the current-voltage (I-V) characteristics of SB-GNRFETs. We carry out accurate approximations of Schottky barrier tunneling, channel charge and current, which provide improved accuracy while maintaining compactness. This SPICE-compatible compact model surpasses the existing model [15] in accuracy, and enables efficient circuit-level simulations of futuristic GNRFET-based circuits. The proposed model considers various design parameters and process variation effects, including graphene-specific edge roughness, which allows complete and thorough exploration and evaluation of SB-GNRFET circuits. We are able to model both single- and double-gate SB-GNRFETs, so we can evaluate and compare these two types of SB-GNRFET. We also compare circuit-level performance of SB-GNRFETs with multi-gate (MG) Si-CMOS for a scalability study in future generation technology. Our circuit simulations indicate that SB-GNRFET has an energy-delay product (EDP) advantage over Si-CMOS; the EDP of the ideal SB-GNRFET (assuming no process variation) is ∼1.3% of that of Si-CMOS, while the EDP of the non-ideal case with process variation is 136% of that of Si-CMOS. Finally, we study technology scaling with SB-GNRFET and MG Si-CMOS. We show that the EDP of ideal (non-ideal) SB-GNRFET is ∼0.88% (54%) EDP of that of Si-CMOS as the technology nodes scales down to 7 nm.

This paper presents the first parameterized, SPICE-compatible compact model of a Graphene Nano-Ribbon Field-Effect Transistor (GNRFET) with doped reservoirs that also supports process variation. The current and charge models closely match numerical TCAD simulations. In addition, process variation in transistor dimension, edge roughness, and doping level in the reservoir are accurately modeled. Our model provides a means to analyze delay and power of graphene-based circuits under process variation, and offers design and fabrication insights for graphene circuits in the future. We show that edge roughness severely degrades the advantages of GNRFET circuits; however, GNRFET is still a good candidate for low-power applications.

We propose a heterogeneous information network mining algorithm: feature-enhanced Rank Class (F-Rank Class). F-Rank Class extends Rank Class to a unified classification framework that can be applied to binary or multiclass classification of unimodal or multimodal data. We experimented on a multimodal document dataset, 2008/9 Wikipedia Selection for Schools. For unimodal classification, F-Rank Class is compared to support vector machines (SVMs). F-Rank Class provides improvements up to 27.3% on the Wikipedia dataset. For multimodal document classification, F-Rank Class shows improvements up to 19.7% in accuracy when compared to SVM-based meta-classifiers. We also study 1) how the structure of the network and 2) how the choice of parameters affect the classification results.

The graphene nano-ribbon field effect transistor (GNRFET) is an emerging technology that received much attention in recent years. Recent work on GNRFET circuit simulations has shown that GNRFETs may have potential in low power applications. In this paper, we review the existing work on GNRFET circuit modeling, compare the two varieties of GNRFETs, Metal-Oxide-Semiconducting-(MOS-)type and Schottky-Barrier-(SB-)type GNRFETs, and thoroughly discuss and explore their respective strengths in terms of delay, power, and noise margin. From this point of view, we discuss their possible applications, especially the use towards low-power computing. Our simulations show that ideal (nonideal) MOS-GNRFET consumes 18% (35%) and 54% (102%) total power as compared to high-performance (HP) Si-CMOS and low-power (LP) Si-CMOS, respectively. SB-GNRFET does not compare favorably to MOS-GNRFET in terms of power consumption. However, ideal (non-ideal) SB-GNRFET has 3% (5.4X) and 0.45% (83.5%) energy-delay product (EDP) compared to Si-CMOS (HP) and Si-CMOS (LP), respectively, while ideal (non-ideal) MOS-GNRFET has 8% (93%) and 1.25% (14.3%) EDP compared to Si-CMOS (HP) and Si-CMOS (LP), respectively.

We consider the channel assignment problem in wireless mesh networks. Due to the limited number of radio interfaces that each node is equipped with, channel assignment must ensure that the interface constraint is obeyed, i.e., the number of different channels assigned to the links incident on a node must be no greater than the number of interfaces the node is equipped with. However, interface constraint may be one of the causes that hinder the performance of some of the existing heuristics. In this paper, we use simulated annealing to solve the channel assignment problem in wireless mesh networks. We propose two neighbor generating approaches that handle the interface constraint in different ways. The first approach starts with an infeasible random solution, and by using the penalty function technique the solution finally converges to a feasible one. The second approach, on the contrary, allows only feasible solutions to be generated during the simulated annealing process. Simulations are conducted that compare our proposed simulated annealing algorithms together with a tabu-based algorithm under different network traffic scenarios. The results show that our algorithms exhibit lower network interference than the tabu-based algorithm.

In this paper, we propose a fuzzy Q-learning-based MIMO configuration mode and MCS level (FQL-MOMS) selection scheme for high speed packet access evolution (HSPA+) systems. The FQL-MOMS selection scheme intends to enhance the system throughput under the block error rate (BLER) requirement guarantee. It will determine an appropriate MIMO configuration mode and MCS (modulation and coding scheme) level for packet data transmission in HSPA+systems, under the situations that the channel status is varying and the channel quality indication (CQI) has report delay. The FQL-MOMS scheme considers not only the reported CQI and the last transmission result but also the BLER performance metric and the transmission efficiency. Moreover, it is effectively configured, where the fuzzy rules and the reinforcement signals for the Q-learning algorithm are sophisticatedly designed. Simulation results show that the proposed FQL-MOMS scheme increases the system throughput by up to 49.3 and 35.9 percent, compared to the conventional adaptive threshold selection (ATS) scheme [12] and the Q-HARQ scheme [14], respectively, under the BLER requirement fulfillment.

In this paper, we propose a hybrid automatic repeat request (HARQ) control scheme by using fuzzy Q-learning algorithm for high speed packet access evolution (HSPA+) systems. The challenge of the HARQ control in HSPA+systems is the selection of MIMO (multiple-input multiple-output) configuration mode and MCS (modulation and coding scheme) level for new data transmission of HARQ, under the situation that the channel quality indication has report delay. The fuzzy Q-learning-based HARQ (FQL-HARQ) scheme can determine an appropriate MIMO configuration mode and MCS level for new data transmission so as to maximize the system throughput under the guaranteed block error rate (BLER) requirement. Simulation results show that, the proposed FQL-HARQ scheme increases the system throughput by up to 70.09% as compared to the conventional adaptive threshold method.

In this paper, we propose a maze-routing-based clock tree routing algorithm integrated with buffer insertion, buffer sizing and topology generation that is able to consider general buffer insertion locations in order to achieve robust slew control. Buffer insertion along routing paths had been mostly avoided previously due to the difficulty to maintain low skew under such aggressive buffer insertion. We develop accurate timing analysis engine for delay and slew estimation and a balanced routing scheme for better skew reduction during clock tree synthesis. As a result, we can perform aggressive buffer insertion with buffer sizing and maintain accurate delay information and low skew. Experiments show that our synthesis results not only honor the hard slew constraints but also maintain reasonable skew.

This paper studies the problem of multicast routing and channel assignment in multi-channel and multi-interface wireless mesh networks. The advantage of the wireless broadcast's nature is used to reduce interference and improve network throughput. The employed network model is first described. Next, a heuristic channel assignment algorithm that makes use of the wireless broadcast's advantage is presented. Simulation results reveal that the proposed heuristic algorithm can reduce interference and increase the network throughput in multi-channel multi-interface wireless mesh networks.

This paper presents an energy conservation scheme, Maximum Unavailability Interval (MUI), to improve the energy efficiency for the Power Saving Class of Type II in IEEE 802.16e. By applying the Chinese Remainder Theorem, the proposed MUI is guaranteed to find the maximum Unavailability Interval, during which the transceiver can be powered down. We also propose new mathematical techniques to reduce the computational complexity when solving the Chinese Remainder Theorem problem. Because the computational complexity is reduced significantly, the proposed MUI can be practically implemented in real systems. The proposed MUI is fully compatible with the 802.16e standard. It provides a systematic way to determine the start frame number, one of the important parameters defined in the standard. In addition to analyzing the computational complexity, simulations and experiments are conducted to evaluate the performance of the proposed algorithms.

This paper presents an energy conservation scheme, maximum unavailability interval (MUI), to improve the energy efficiency for the Power Saving Class of Type II in IEEE 802.16e. By applying the Chinese remainder theorem, the proposed MUI is guaranteed to find the maximum Unavailability Interval, during which the transceiver can be powered down. The proposed MUI only dynamically adjusts one parameter defined in the standard. In addition, it is fully compatible with 802.16e standard. We also propose a new technique to reduce the computational complexity when solving the Chinese remainder theorem problem. Simulation and analysis have been conducted to evaluate the performance.

Wireless mesh networks (WMNs) are emerging as a favorable technology for last-mile Internet access. Nodes in WMNs can be equipped with multiple interfaces which work in different channels to increase the available bandwidth. However, efficient channel assignment schemes are still needed due to the interference effect and the limited number of orthogonal channels. In this paper, we consider the channel assignment and routing for dynamic traffic in WMNs. We adopt the static channel assignment strategy to the network interfaces. The problem is simplified into two sequential stages. The first is to assign channels to interfaces while the second is to determine the route for each coming traffic demand. We propose a Mixed Integer Linear Programming (MILP) formulation to the problem and develop a simulated annealing based channel assignment algorithm for the channel assignment. The shortest path routing is adopted for the dynamic traffic. Simulation results show the network throughput and blocking probability under different network scenarios.

This paper presents the dynamic external home agent (x-HA) assignment, fast authentication, and pre-authentication in mobile virtual private networks (VPNs). The proposed architecture is based on the mobile VPN proposed by the IETF, which adopts mobile IP and IPsec. The IETF solution, however, leads to two questions: where should we put the x-HA and how should we trust the x-HA? We propose to assign the x-HA dynamically so the hand-off latency and end-to-end latency could be reduced significantly. By using diameter mobile IPv4 application, we also propose a technique such that the x-HA can be associated with the VPN securely. In addition, we also propose fast authentication and pre-authentication to further reduce hand-off delay. The proposed technique has been implemented in a mobile VPN testbed. Performance analysis based on empirical experiments is discussed.

As the technology advances to increase the number of wavelengths in fiber links, multigranularity optical cross-connects (MG-OXCs) have emerged as a solution to reduce the manufacturing cost of the traditional optical cross-connects (OXCs). In this paper, we aim to provide an efficient fault-recovery protection scheme for the lightpaths in the MG-OXC networks. A segment-based protection scheme, called tunnel based segment protection (TSP) is proposed to recover the communications interrupted by a fiber cut. TSP first allocates all the tunnels off-line according to the historical traffic matrix and then starts to serve the incoming requests. When allocating a tunnel, a backup tunnel is always allocated as well. Consequently, a lightpath is naturally divided into segments according to the switching types along the path. Therefore, after a working path is found for a connection request, only a shared backup path for those segments in the corresponding wavelength-switching layers need to be found. In addition, TSP utilizes wavelength-switching ports efficiently since working and backup tunnels can share the same wavelength-switching ports at two ends of the tunnel. Simulation results show that the network performance is improved comparing to adapt a straightforward path protection scheme for MG-OXC networks.