To provide mobility assistance for people with disabilities, pedestrian network data that includes accessibility attributes within public spaces is required. The freshness of data is necessary as public space conditions change frequently; however, its regular maintenance incurs substantial costs. In this paper, we propose a data platform for an accessible pedestrian network with a workflow similar to continuous software development. With this approach, the platform aims to allow local governments and citizens to maintain data in a collaborative and sustainable manner. This paper reports the initial phase of our project aiming at realizing such a platform; we designed and prototyped a platform based on this idea and conducted an actual field experiment in a specific area of Tokyo. Through this experiment, we demonstrated the feasibility of this idea and gained valuable insights for practical implementation.

Under the COVID-19 pandemic, it is necessary to balance social distancing and continuous economic activities. In this study, we report on our developed service that forecasts the congestion level of regional commercial facilities using point-of-sales (POS) statistics. POS statistics data were collected for over a year from 150 commercial facilities in Tokyo. Through the analysis of a total of over 100 million customers, we clarified the factors that affect congestion levels of commercial facilities in each ward of Tokyo. Based on this analysis, we developed a congestion forecast model that predicts future congestion levels from several factors such as a big event, business restrictions, and weather. We implemented a web service incorporating this model and published estimated congestion levels both on our website and a television program. The experimental results show that the model has a high prediction accuracy with a coefficient of determination greater than 0.95 on average, which implies that big data from POS has great potential for value creation under the pandemic.

In today’s technology-dominated world, in order to better equip the next generation of youth with technological skills suitable for future jobs, pre-tertiary and early tertiary curricula are being significantly revamped all over the world. In line with this drive, as a STEM discipline, Computer Science (CS) is also being widely incorporated in recent curricular initiatives. Information security is one of core areas of CS. Security concepts often entail esoteric mathematical ideas which are difficult to explain to early-stage learners, which necessitates contriving new and engaging ways of teaching. This paper deals with teaching of one such security concept – namely, DiffieHellman key exchange protocol – to early-stage learners. Traditionally, a color-mixing analogy has been used for introducing the concept of Diffie-Hellman key exchange protocol. Although this approach elegantly exemplifies the discrete logarithm problem on which the protocol is based, depending on how the lesson is executed, it can be passive, or require a new supply of liquid colors for each lesson. Therefore, we have developed a digital version of the color-mixing approach – while retaining active student participation and tangibility – by using color sensors and Raspberry Pi. We also propose a mission-based lesson plan based on the tangible tool for enabling young pupils to comprehend difficult concepts. Our pilot study using the tangible-tool-based lesson plan showed promising results as the participants found the lesson engaging and enriching. We also believe, as an unplugged approach, our low-cost and reusable tangible tool can help ensure universal access to education in developing countries.

Self-management is recognized as an essential component of care for atopic dermatitis (AD), as for other chronic diseases. Wearable technology has the potential to help patients with AD improve their self-management by allowing them to monitor itching, one of the most burdensome symptoms which can lead to impaired quality of life. In this research we aimed to investigate patient experience and acceptance of a wrist-worn wearable system to measure nocturnal scratch behavior and provide objective feedback based on the measured data. To provide a comfortable and easy-to-use system, a wristband and user interface were co-designed with a patient with AD. We conducted a 14-day field trial in which four patients used our prototype. The results showed that the prototype was generally well accepted and would be helpful in understanding their itching conditions and enhancing current therapeutic strategies. We then discuss the implications of our results for designing wearable healthcare systems for patients with AD.

Childhood atopic dermatitis (AD) can have significantly negative impact on children and their primary caregivers' quality of life. Caregiver's reduced quality of life often results in poor adherence to treatment, which is a major cause of treatment failure in childhood AD. This research aims to investigate caregiver experiences and potential needs and to create a smartphone-based tracking system to help them enhance current therapeutic strategies to manage their children's AD. In this paper, we describe the first iteration of a user-centered design process to develop an effective and easy to use system. We first conducted a need-finding study involving 173 parents of children with AD and patients to identify functionalities tailored to the target users. We then developed a mock-up application to demonstrate these functionalities, including symptom drawing, care reminder, and content recommendations. Initial user testing with 7 participants showed that the initial design concept was generally well accepted and would be helpful in caring for children with AD. We discuss the challenges and opportunities for the further improvements.

With the rapid advances of Internet of Things (IoT) technologies in recent years, more devices around us are becoming connected to the Internet. Such devices are often equipped with web API, which allows them to work as a whole in smart buildings or cities, not as a standalone object that conventional devices used to be. In order to make these device API practical, security cannot be disregarded because the impact of a security breach in physical objects tends to be larger, as it directly affects the physical environment we live in. However, enforcing security for such devices is challenging, because it may consist of heterogeneous devices including those with limited resources. Additionally, devices in smart building environment may be attached or removed at any time dynamically. In order to fill up this gap, we present an access control framework for API-enabled devices in smart buildings. To accommodate a dynamic environment in smart buildings, we split security manager as a third party in the system. Complex security computations are delegated to the security manager so that resource-constrained devices can be securely handled as well in our framework. To guarantee only authorized user can access the device, the device is forced to ask security manager to evaluate requests. The proposed framework is implemented in the real smart building, which consists of more than 300 devices and its performance is evaluated by conducting a various of experiments. The average of response time has less than 0.1 seconds, which indicates that the proposed framework is reasonable to be practically used in a real smart building.

Improving energy efficiency of smart buildings becomes more complex in the era of Internet of Things (IoT) where networked devices supply unprecedented high-resolution energy related information. As data acquisition and device control services are integrated into the building management platform by using web-based RESTful APIs, fine-grained context-based automatic control ability based on sensed and metered situations using a programmable approach is enabled. Rule-based approaches have been applied to design controllers for an individual device or a sub-system in buildings. However, the rules are static and usually mixed with the application logics. To improve energy efficiency by allowing smart devices to work in a collaborative way, a flexible programming architecture, which involves all the energy related factors, is required for complex context-based control of devices. In this paper, we propose DCRDL, a rule definition language that enables energy control policy designers to write flexible rules to control the behaviors of devices based on various levels of energy related information. We conducted several experiments with policies written in DCRDL in a real smart building, and the result shows that DCRDL is an efficient tool for situation-based device control for energy efficiency in IoT-enabled smart buildings.

Adopting IT as an integral part of business and operation is certainly making the healthcare industry more efficient and cost-effective. With the widespread digitalization of personal health information, coupled with big data revolution and advanced analytics, security and privacy related to medical data — especially ensuring authorized access thereto — is facing a huge challenge. In this paper, we argue that a fine-grained approach is needed for developing access control mechanisms contingent upon various environmental and application-dependent contexts along with provision for secure delegation of access-control rights. In particular, we propose a context-sensitive approach to access control, building on conventional discretionary access control (DAC) and role-based access control (RBAC) models. Taking a holistic view to access control, we effectively address the precursory authentication part as well. The eTRON architecture — which advocates use of tamper-resistant chips equipped with functions for mutual authentication and encrypted communication — is used for authentication and implementing the DAC-based delegation of access-control rights. For realizing the authorization and access decision, we used the RBAC model and implemented context verification on top of it. Our approach closely follows regulatory and technical standards of the healthcare domain. Evaluation of the proposed system in terms of various security and performance showed promising results.

Context-awareness is a quintessential feature of ubiquitous computing. Contextual information not only facilitates improved applications, but can also become significant security parameters -- which in turn can potentially ensure service delivery not to anyone anytime anywhere, but to the right person at the right time and place. Specially, in determining access control to resources, contextual information can play an important role. Access control models, as studied in traditional computing security, however, have no notion of context-awareness; and the recent works in the nascent field of context-aware access control predominantly focus on spatio-temporal contexts, disregarding a host of other pertinent contexts. In this paper, with a view to exploring the relationship of access control and context-awareness in ubiquitous computing, we propose a comprehensive context-aware access control model for ubiquitous healthcare services. We explain the design, implementation and evaluation of the proposed model in detail. We chose healthcare a representative application domain because healthcare systems pose an array of non-trivial context-sensitive access control requirements, many of which are directly or indirectly applicable to other context-aware ubiquitous computing applications.

Spatial information is very important because context such as location information is one of the key issues to realize ubiquitous spatial infrastructure. However, there are many specifications for spatial information model and establishing a common infrastructure for spatial information model is difficult. To solve the problem, we propose a new spatial information model based on ucR. Our model has high scalability because it is based on dynamic linking. We use triplestore to build our database, and its schema is more flexible and extensible than relational database schema. Moreover, we propose a flexible method to create new geographic identifiers by using combination of registered geographic identifiers. In addition, we realize the interoperability between our model and other spatial information models.

Lateral distance between two traffic participants is an important context for intelligent transportation systems for realizing a collision prediction system. Obtaining lateral distance requires costly hardware, prohibiting traffic participants such as pedestrians and/or bicyclists to receive benefits of lateral distance information for securing their safety. In this paper, a time-of-arrival (TOA) based bilateration is proposed for estimating relative lateral distance using ultra-wideband impulse radio (UWB-IR). Ranging error of UWB-IR systems affecting the estimation accuracy of lateral distance is coped with applying a low pass filter to angular data. Experimental results show that the estimation error is reduced from 8 m to 3 m when the relative distance between a target vehicle and a pedestrian is less than 15 m, using a portable UWB-IR system with 30 cm ranging accuracy.

An ultra-small, high-data-rate, low-power 1-cc computer (OCCC) with an UWB-IR (ultra-wideband impulse-radio) transceiver was developed for a wireless sensor network. Thanks to bear-chip implementation and a flexible printed circuit board, the size of the computer is only 1 cm3. To achieve 10-Mbps data rate, a middle-class 32-bit microcontroller, which has both a bus interface and a USB 2.0 controller, was selected. Low-power techniques, such as transition of microcontroller status to standby mode by using an external real-time clock during wait times, power shutdown of halted circuits, and detailed control of UWB-IR transceiver status, are applied. The effect of these low-power techniques is verified by measuring the time history of current consumption of the OCCC. It was confirmed that the OCCC can provide wireless communication at a transmission rate of 258 kbps over a distance of 30 m.

In achieving the mobility assistance for the individuals with different disabilities, it is required to recognize places with different granularities defined based on human interest, which is hard to be accomplished using traditional GPS-based approaches. In order to meet this requirement, a space-identifying ubiquitous infrastructure designed upon the concept of the universal design has been proposed, which is capable of constructing a service that is aware of places of human interest using ubiquitous computing technologies. Upon this infrastructure, two case studies are performed in the existing civil space, consisting of a pedestrian navigation service for the individuals with different needs, and a mobility assistant service for the visually-impaired. Through these case studies, the possibilities of the proposed infrastructure are discussed.

The key issue in achieving a pedestrian navigation service is to grasp the spatial context of pedestrians, which is mainly characterized by the places of their interest. We have developed a pedestrian navigation system uNavi, based on our proposed infrastructure that is capable of associating information services to the places of human interest. This paper focuses on the implementation and deployment of the system. Our current implementation realizes a detailed and timely navigation, by presenting landmark-based instruction of guidance using the spatial semantics stored locally. In addition, thanks to the feature of flexible definition of places achieved by our infrastructure, uNavi has a potential to assist the mobility of the disabled. Through the case studies of several large-scale deployments, the feasibility and effectiveness of our approach is discussed in this paper.

Ubiquitous Computing poses new challenges for the software engineering community. The T-Engine platform consisting of standard real-time kernel, T-Kernel, running on the standard hardware with networking facility creates broad application opportunities based on the collaboration of cutting edge microelectronics, software and embedded system technologies. However, to realize the true potential of such a system in a ubiquitous computing environment, we need to overcome software engineering issues among many hurdles we encounter. We describe such issues and the future challenges inherent in the ubiquitous computing based on our experience of using Ubiquitous Communicator terminal that is based on T-Engine.

In this paper, we propose a robust natural language interface called CASIS for controlling devices in an intelligent environment. CASIS is novel in a sense that it integrates physical context acquired from the sensors embedded in the environment with traditionally used context to reduce the system error rate and disambiguate deictic references and elliptical inputs. The n-best result of the speech recognizer is re-ranked by a score calculated using a Bayesian network consisting of information from the input utterance and context. In our prototype system that uses device states, brightness, speaker location, chair occupancy, speech direction and action history as context, the system error rate has been reduced by 41% compared to a baseline system that does not leverage on context information.

The expanding market for digital content increases the demand to transfer electronic value through open networks. This paper describes the Ticket Transfer Protocol (TTP), which enables electronically transferable tickets to directly move between two personal tamper-proof devices. The applied two-phase commit protocol for the transfer realizes the ACID (atomicity, consistency, isolation, durability) transaction properties without any external coordinators. Moreover, this paper addresses the initial implementation of a secure TTP, enabling the detection of message replays by attackers, and evaluates the size of its logging field in the transaction. We conclude that TTP has enough reliability to transfer electronic tickets directly between personal ticket wallets.

We propose a network layer protocol denoted ACRP (Auto-Configurated Routing Protocol) equipped with a function that automatically configures routing addresses and routing tables for a large scale network system made up of multiple connected physical networks. The goals of the work presented, are to enable adding and deleting physical networks during practical use and designing the protocol in such a way that the auto-configuration is finished within a few minutes. By simulating ACRP, we have succeeded in determining the algorithm structures for the routing tables protocol, that satisfy these requirements in a network with approximately 400000 nodes. This work will contribute to the improvement of expandability and maintainability of control LANs for intelligent buildings, etc.

Internet commerce is increasing the demands of service integrations by sharing XML-based catalogs. We propose the PCO (Portable Compound Object) data model supporting semantic inheritance to ensure the synonymy of heterogeneous semantics among distributed schemas that different authors define independently. Also, the PCO model makes semantic relationships independent of an initial class hierarchy, and it enables rapid schema evolution across the entire Internet business. This preserves semantic interoperability without changing pre-defined classes. We have also encoded the PCO model into two XML-based languages: the PCO Specification Language (PSL) and the Portable Composite Language (PCL). This paper demonstrates that intermediaries defining service semantics in PSL can automatically integrate multiple suppliers' PCL catalogs for their agent-mediated services.

Proposes a new decentralized architecture for electronic markets, called Digiket (DIGItal marKET), as an alternative to traditional virtual malls. The present Internet commerce consists of relatively small closed markets; so, new frameworks that enable Web-based stores and malls to share their services worldwide are strongly desired. Digiket separates electronic commerce functions (such as content authoring, catalog delivery, intermediary services, shopping assistants and transaction processing) from traditional mall sites, and decentralizes each of them independently. Digiket's architecture is unique in that it requires no central coordinators for the distributed components. Instead, the PCO (Portable Compound Object) language, a lingua franca for Digiket, connects the components to each other. We have also implemented the PCO language and a user agent client named OpenBasket, to demonstrate a shopping application on Digiket. The demonstration shows that a consumer can order arbitrary goods described in PCO without vendor barriers.

In an open system standards environment, a formal specification can be shared by all of its implementations, which results in the sharing of development cost. This paper presents a specification-based adaptive test case generation (SBATCG) method for generating validation test cases and a specification-based adaptive consistency check generation (SBACCG) method for generating on-line consistency checks for implementations developed from a model-based specification. The SBATCG (SBACCG) method first derives test cases (consistency checks) through rigorous exploration of a model-based specification, adapts the test cases (consistency checks) to the program structure of a particular implementation, and then produces test cases (consistency checks) that are particularly suitable for the implementation. Testing does not guarantee a program's freedom from faults. The results of the fault-injection experiment show that the SBACCG method can complement the SBATCG method.

In order to solve the problem of inopportune preemption in multiprogrammed multiprocessor synchronization, two strategies which are applicable to real-time systems have been investigated: preemption-safe locking and wait-free synchronization. Both of them, however, have a problem for use in the implementation of a real-time kernel. Preemption-safe locking has the drawback that the preemption cost becomes large; while wait-free operations on complex data structures are generally very inefficient and are not practical. We propose a novel approach to multiprogrammed multiprocessor synchronization, called the SPEPP (Spinning Processor Executes for Preempted Processors) synchronization, with which the preemption cost can be reduced to almost zero, while operations on complex data structures can be realized with reasonable efficiency. This paper presents the two algorithms of the SPEPP synchronization and their extensions, and demonstrates its effectiveness through the performance measurements of real-time kernels implemented with the SPEPP synchronization algorithms.

This paper proposes a distributed shared memory, Window Real-Object (WROL which facilitates the construction of GUI applications with a set of cooperating parallel units running on multiple machines.To support unit cooperation, the WRO provides a shared data structure storing interaction objects displayed in a window among multiple machines.It also provides an event mechanism called absfrac[ everm to support control transfer among these units.Abstract events are generated when the shared data structure is updated, and invoke the units sharing the WRo.Both the function and mechanism of the WRO are tailored for GUI applications.The WRO provides spatia~addressing to the data structure, which is implemented efficiently using an R-tree.It also adopts aflli-replication algorithm as a shared-memory coherenee scheme.Consequently, the WRO can be implemented with adequate performance on a usual workstation environment.

This paper describes firmware and hardware support necessary for constructing easy-to-understand and high performance operating systems including language translators and interpreters. Basic principles are one-to-one correspondence between logical hierarchy and physical hierarchy, and vertical migration. Implementation of monitors in firmware and architectural support for it are discussed, and a sample system is shown. Architectural support for user microprogramming is then discussed and an example is shown. After a total system firmware structure is discussed, an experiment of vertical migration is described. It is shown that a proper selection of modules for migration is extremely important. It is suggested that the direction shown in this paper is one of future directions of computer systems.

This paper deals with an automatic recovery mechanism designed to prevent the occurrence of subtract errors at the computer architecture level. This mechanism always detects the occurence of subtract errors whenever addition or subtraction is performed. If a subtract error is detected, backtracking to a certain location is carried out, and from there recomputing is performed in order to realize the required precision. An adaptive algorithm required for this mechanism is described in detail. An experimental adaptive computer was implemented on a Burroughs B1700. The evaluation of the experiments proves that the inherent possibilities of dynamic microprogramming play a very important role in realizing this mechanism, and that the proposed mechanism will be useful for the development of future high-level computer systems.