Kee-Wook Rim

A timeliness-guaranteed kernel model-DREAM kernel-and implementation techniques

An essential building-block for construction of future real-time computer systems (RTCSs) is a timeliness-guaranteed operating system. The first co-author recently formulated a model of an operating system kernel which can support both real-time processes and new-style real-time objects with guaranteed timely services. The model has been named the DREAM kernel. The key emphasis in formulating the DREAM kernel was in realization of guaranteed timely service capabilities with minimal loss of hardware utilization. This paper presents a summary of the main structuring principles that were exploited to realize guaranteed timely service capabilities together with modularity and expandability in the DREAM kernel. A prototype implementation of the DREAM kernel, v.D2, has been produced by the authors to run on a network of PCs connected by an Ethernet. Several implementation techniques that were adopted during the course of this prototype implementation and may be applicable to other real-time kernel development environments, are briefly discussed in this paper. The prototype kernel (v.D2) has been used to run a real-time object structured non-trivial defense C3 application together with a real-time simulator of the application environment.

Localized Approximation Method Using Inertial Compensation in WSNs

Sensor nodes in a wireless sensor network establish a network based on location information, set a communication path to the sink for data collection, and have the characteristic of limited hardware resources such as battery, data processing capacity, and memory. The method of estimating location information using GPS is convenient, but it is relatively inefficient because additional costs accrue depending on the size of space. In the past, several approaches including range-based and range-free have been proposed to calculate positions for randomly deployed sensor nodes. Most of them use some special nodes called anchor nodes, which are assumed to know their own locations. Other sensors compute their locations based on the information provided by these anchor nodes. This paper uses a single mobile anchor node to move in the sensing field and broadcast its current position periodically. We provide a weighted centroid localization algorithm that uses coefficients, which are decided by the influence of mobile anchor node to unknown nodes, to prompt localization accuracy. In addition, this study lowered the error rate resulting from difference in response time by adding reliability for calculating and compensating detailed location information using inertia.

Interactive middleware architecture for lifelog based context awareness

Due to the development of IT convergence, a wide variety of information is being produced and distributed rapidly in digital form. Lifelog based context awareness is a technology that provides a service automatically based on perceived situational information in ubiquitous environments. To offer customized services to users, the technology of acquiring lifelog based context information in real time is the most important consideration. We propose the interactive middleware architecture for lifelog based context awareness in distributed and ubiquitous environments. Conventional middleware to support ubiquitous environments stores and manages the situational information and service content acquired by centralized storage or a DBMS. Centralized situational information and service content management may impede the autonomy of mobile nodes and the interoperation between different middle software. The proposed method designs a system that can distribute and manage situational information in mobile nodes using mobile devices in distributed and ubiquitous environments and share the service content between interactive middleware through publication. The application system designed in this study was used in a scenario providing situational perception based mobile service and proved to be useful.

Bio-Interactive Healthcare Service System Using Lifelog Based Context Computing

Intelligent bio-sensor information processing was developed using lifelog based context aware technology to provide a flexible and dynamic range of diagnostic capabilities to satisfy healthcare requirements in ubiquitous and mobile computing environments. To accomplish this, various noise signals were grouped into six categories by context estimation and effectively reconfigured noise reduction filters by neural network and genetic algorithm. The neural network-based control module effectively selected an optimal filter block by noise context-based clustering in running mode, and filtering performance was improved by genetic algorithm in evolution mode. Due to its adaptive criteria, genetic algorithm was used to explore the action configuration for each identified bio-context to implement our concept. Our proposed Bio-interactive healthcare service system adopts the concepts of biological context-awareness with evolutionary computations in working environments modeled and identified as bio-sensors based environmental contexts. We used an unsupervised learning algorithm for lifelog based context modeling and a supervised learning algorithm for context identification.

Efficient Adaptations of the Non-Blocking Buffer for Event Message Communication between Real-Time Threads

Enabling message communication among concurrent computing threads without relying on mutual exclusion (i.e., locking) is highly desirable in real-time computing systems. This paper presents a refined version of the Non-Blocking Buffer (NBB), which is a lock-free interaction mechanism that enables efficient event-message communication between a single producer thread and a single consumer thread. The NBB scheme presented here contains improvements over the previous version in two aspects. First, application designers now have the flexibility of choosing the consumers retry strategy for the case when the buffer is empty but the producer is in the middle of inserting an item. Second, in the refined version the producer inserts pointers to data items into the buffer whereas the consumer obtains copies of the items. This design is consistent with the fact that shared heap management must be avoided to enable fully lock-free interaction between the producer and the consumer. This paper also discusses the approaches based on the NBB mechanism for supporting all conceivable producer-consumer scenarios.

3DE: selective cluster head selection scheme for energy efficiency in wireless sensor networks

The traditional cluster-based routing method is a typical method for enhancing an energy efficiency, which selects cluster head in order to send the aggregated data arriving from the nodes in cluster to a sink. However, caused by the frequent information exchange between selected cluster head and nodes of cluster in setup phase of the cluster formation and direct transmission between isolated nodes which are excluded from the all clusters and sink in steady-state phase, it is necessary to minimize the unnecessary energy dissipation using the equal distribution of cluster heads. We propose an efficient cluster-based routing scheme, called 3DE. In order to configure the optimum distribution of cluster, 3DE selects new cluster head using the information such as direction obtained from upper level cluster head, distance among nodes in the cluster, residual energy and density. Thus this study prolongs the network lifetime and provides equal opportunity for being cluster head.

Design of Diet Recommendation System for Healthcare Service Based on User Information

In the recent aging society, studies on health care services have been actively conducted to provide quality services to medical consumers in wire and wireless environments. However, there are some problems in these health care services due to the lack of personalized service and the uniformed way in services. For solving these issues, studies on customized services in medical markets have been processed. However, because a diet recommendation service is only focused on the personal disease information, it is difficult to provide specific customized services to users. This study provides a customized diet recommendation service for preventing and managing coronary heart disease in health care services. This service provides a customized diet to customers by considering the basic information, vital sign, family history of diseases, food preferences according to seasons and intakes for the customers who are concerning about the coronary heart disease. The users who receive this service can use a customized diet service differed from the conventional service and that supports continuous services and helps changes in customers living habits.

Alternative Cluster Head Selection Protocol for Energy Efficiency in Wireless Sensor Networks

The traditional cluster routing method is a typical method for enhancing an energy efficiency, which selects cluster head in order to send the aggregated data arriving from the nodes in cluster to a base station. However the major challenges are the equal distribution of each cluster over the whole sensor network and the energy dissipation caused by the frequent information exchange between selected cluster head and nodes in the cluster in every setup phase of cluster formation.In this study, in order to configure the optimum distribution of cluster throughout the sensor network, cluster head is alternatively selected using the information such as direction information obtained from upper level cluster head, distance among nodes in the cluster, residual energy and density. In addition, this study suggests the modified cluster head selection scheme which uses the conserved energy in the steady-state phase by reducing unnecessary communications of unchanged nodes between selected cluster head and previous cluster head in the setup phase, and thus prolongs the network lifetime and provides equal opportunity for being cluster head.

An embedded integration prototyping system based on component technique

Nowadays in the development of embedded system, cutting-edge embedded system products are quickly disappearing from the markets because of their short product development period which shortens the product life cycle. Therefore, strengthening its competitiveness and minimizing its development cost can be said to be one of the most important factors. For this motive, an Embedded Integration Prototyping (IP) system based on Component Technique was designed and implemented through this paper. The system is composed of Physical Prototyping (PP) providing the environment in which the product can be tested by using Actuator(Motor), Sensor and reusable Blocks, and Virtual Prototyping (VP) in which visual test on the product can be carried out by applying various components and libraries based on technique related to the computer. And, IP System was built in order to mutually compensate for drawbacks latent in both of physical and virtual prototyping environment by making use of component module. The module will be able to enhance the product competitiveness, through spending less time in developing kinds of the component owning almost same features, using it again for different embedded system products, and accordingly minimizing spent cost and time for developing the component.

Development of Design Recommender System Using Collaborative Filtering

It is an important strategy to investigate customer’s sensibility and preference in the merchandise environment changing to the user oriented. We propose the design recommender system, which exposes its collection in a personalized way by the use of collaborative filtering and representative sensibility adjective on textile design. We developed the multi-users interface tool that can suggest designs according to the user’s needs in the design industry. In this paper, we adapt collaborative filtering to recommend design to a user who has a similar propensity about designs. And we validate our design recommender system according to three algorithms in off-line experiments. Design merchandizing may meet the consumer’s needs more exactly and easily with this system.