Dong-Ik Oh

Utilization Bounds for N-Processor Rate MonotoneScheduling with Static Processor Assignment

We consider the schedulability of a set of independent periodic tasks under fixed priority preemptive scheduling on homogeneous multiprocessor systems. Assuming there is no task migration between processors and each processor schedules tasks preemptively according to fixed priorities assigned by the Rate Monotonic policy, the scheduling problem reduces to assigning the set of tasks to disjoint processors in such a way that the Monotonic policy, the scheduling problem reduces to assigning the set of tasks to disjoint processors in such a way that the schedulability of the tasks on each processor can be guaranteed. In this paper we show that the worst case achievable utilization for such systems is between n(21/2-1) and (n+1)/(1+21/(n+1)), where n stands for the number of processors. The lower bound represents 41 percent of the total system capacity and the upper bound represents 50 to 66 percent depending on n. Practicality of the lower bound is demonstrated by proving it can be achieved using a First Fit scheduling algorithm.

R-LIM: an Affordable Library Search System Based on RFID

With a large volume of materials todays libraries carry, locating the exact position of materials is time-consuming. This is not true just for poorly managed libraries, but also for well maintained libraries. In the former case, the problem is rather serious. Even though a material is somewhere in the library, if we cannot locate the material, the fundamental roles of the library may be challenged. In the latter case, one still needs to go through a tedious shelf searching process to locate the material. In this study we propose an affordable RFID based library management system named R-LIM which eases the process of locating books in the library. In an earlier version of R-LIM, expensive RFID antennas had to be placed on every shelf to acquire location information. In this new version, we replace the antennas with inexpensive tags to make the system more affordable. By associating book-tag IDs with shelf-tag IDs through periodic tag scanning, we can identify the exact location of the book we are searching for. This paper describes the localization algorithm of R-LIM, and explains how it can be integrated with other parts of the system

A Study on the Implementation of RFID-based Autonomous Navigation System for Robotic Cellular Phone(RCP)

Industrial and economical importance of CP(Cellular Phone) is growing rapidly. Combined with IT technology, CP is one of the most attractive technologies of today. However, unless we find a new breakthrough in the technology, its growth may slow down soon. RT(Robot Technology) is considered one of the most promising next generation technologies. Unlike the industrial robot of the past, today`s robots require advanced features, such as soft computing, human-friendly interface, interaction technique, speech recognition object recognition, among many others. In this paper, we present a new technological concept named RCP (Robotic Cellular Phone) which integrates RT and CP in the vision of opening a combined advancement of CP, IT, and RT, RCP consists of 3 sub-modules. They are (RCP Mobility System), , and . The main focus of this paper is on which combines an autonomous navigation system of the RT mobility with CP. Through , we are able to provide CP with robotic functions such as auto-charging and real-world robotic entertainment. Ultimately, CP may become a robotic pet to the human beings. consists of various controllers. Two of the main controllers are trajectory controller and self-localization controller. While the former is responsible for the wheel-based navigation of RCP, the latter provides localization information of the moving RCP With the coordinates acquired from RFID-based self-localization controller, trajectory controller refines RCP`s movement to achieve better navigation. In this paper, a prototype of is presented. We describe overall structure of the system and provide experimental results on the RCP navigation.

A study on development of home Mess-Cleanup Robot McBot

Autonomous and automatic home Mess-Cleanup Robot (Mcbot) is newly developed in this paper. So far, the vacuum-cleaner had made the burden of house chore lighten but the operational labor of a vacuum-cleaner had been so severe. Recently, the cleaning robot was commercialized to solve home cleaning labor problem but it also was not successful because it still had a problem of mess-cleanup, which was the clean-up of big trash and the arrangement of newspapers, clothes, etc. The cleaning robot just vacuum dust and so small trash but has no function to arrange the mess-up and throw away the big trash in house. For this reason, the market for the cleaning robot is not yet actively built up. So, we develop a new home mess-cleanup robot McBot to perfectly overcome this problem. It needs functions of agile navigation and novel manipulation system for mess-cleanup. The autonomous navigation system has to be controlled for the full scanning of living room and for the precise tracking of the desired path, It must be also able to recognize the absolute position and orientation of the self and to distinguish the mess object to clean-up from obstacle object to just avoid. The manipulator, which is not needed in the vacuum-cleaning robot, has the functions to distinguish big trash to clean from mess objects to arrange, to use its discretion in according to the form of mess objects and to properly carry them to the destination. We use the RFID system to sense them in this paper and propose the new disposition algorithm to have RFID tags installed on the floor and objects indoor. Then, it should be an intelligent system so that the messed-cleanup task can be autonomously performed in a wide variety of situations and environments. It needs to also have an intelligent interaction function for the human-friendly communication. Finally, the good performance of the developed McBot is confirmed through the results of the mess-cleanup experiments.

CPR localization using the RFID tag-floor

In this paper, we describe our approach to achieve accurate localization using RFID for Cellular Phone Robot (CPR). We solely rely on RFID mechanism and complement coordinate errors accumulated during the wheel-based CPR navigation. We especially focus on how to distribute RFID tags (tag pattern) and how many to place (tag granularity) on the floor to accomplish efficient navigations. We define the error in navigation and use it to compare the effectiveness of various RFID floor settings through a simulation. Identified tag patterns and granularities would be useful to many USN applications where the adoption of RFID technology is appropriate.

Extracting Information from XML Documents by Reverse Generating a DTD

Information contained in XML documents cannot properly be interpreted without an appropriate DTD. However, XML documents collected from the web may not always be accompanied by the corresponding DTD, so that extracting information from such sources may not be easy. In this study, we reverse construct a DTD from DTD-unknown XML sources, and use it to extract information from XML inputs. The DTD construction module developed is designed to scan input XML files in 1-path, where most other implementations use 2-path approach. Developed modules provide clean Java programming interfaces as well, so that it can be integrated with other web applications seamlessly.

Optimization of Ada '95 tasking constructs

The 1995 revision of the Ada programming language added several new features related to multitasking. These new features open up new implementation questions. In particular, it is appropriate to revisit the subject of compiler and runtime system optimization techniques for Ada multitasking. The existence of GNAT provides an opportunity to study these problems, as well as some more general and longer-standing questions. We study two areas of optimization. The first area is reduction in the number of operating system service calls. We concentrate on the use of different locking policies which control the degree of parallelism within the runtime system. The second area of optimization is to restrict the runtime system using the new pragma Restrictions. In particular, we produce a restricted RTS which excludes task abortion and the asynchronous transfer of control. Performance comparisons between different versions of GNARL are provided, and ways of managing them are also discussed.

Low-level Ada tasking support for GNAT-performance and portability improvements

GNARL is the tasking runtime system of the Gnu NYU Ada95 Translator (GNAT). GNARL is divided into two main layers, the lower of which isolates dependences on a particular host operating system or real-time kernel. For portability, the primary implementation of this lower level accesses OS services via the POSIX interfaces. In this paper we describe our recent redesign of the low-level interface, to improve both performance and portability. Performance comparisons between the new and old runtime system on Solaris2.4 show up to approximately 40 percent improvement on tasking related operations.

Plasma t-PA and PAI-1 antigen concentrations in non-insulin dependent diabetic patients: Implication for diabetic retinopathy

Parameters of fibrinolysis, including basal plasma tissue type plasminogen activator (t-PA) and plasminogen activator inhibitor type 1 (PAI-1) antigen levels were studied in 49 non-insulin dependent diabetic patients (23 men, 26 women: ages 51.3 +/- 14.9 years) and 16 age matched non-diabetic subjects (9 men, 7 women ages 49.8 +/- 12.2 years) as a control group. Compared to a control group, the diabetic patients had a significantly higher mean plasma t-PA antigen (4.94 +/- 2.68 vs 3.20 +/- 2.30 ng/ml) and PAI-1 antigen (34.86 +/- 16.71 vs. 17.60 +/- 15.36 ng/ml) levels (P < 0.05). Significant univariate correlations were observed between t-PA and body mass index (BMI) (P = 0.0009, r = 0.7217), and PAI-1 were positively correlated with BMI and FBS (fasting blood sugar) in the total diabetic patients (P = 0.0003, r = 0.7217; P = 0.0477, r = 0.2858, respectively). In diabetic patients with proliferative diabetic retinopathy, both PAI-1 and t-PA antigen levels were significantly lower than those of diabetic patients with negative or background retinopathy (P = < 0.05). There were no significant differences of the plasma t-PA and PAI-1 levels between diabetic patients with micro- and macroproteinuria. This study conducted on non-insulin dependent diabetic patients suggests that they have significantly higher t-PA and PAI-1 antigen levels than do control subjects, and these findings appear to correlate negatively with proliferative retinopathy observed among the patients studied.

Euglobulin fibrinolytic activity in NIDDM patients

The euglobulin fibrinolytic activity was measured in 56 non-insulin-dependent diabetics and 118 age-matched healthy controls before and after venous occlusion for 5 min at 100 mmHg of the left antecubital vein. In the basal state, fibrinolytic activity was impaired in diabetics compared with controls (93.1 +/- 6.7 vs 101.6 +/- 0.9 BAU) (P less than 0.05) and plasma fibrinogen level was increased but this did not reach statistical significance (467.3 +/- 264.1 vs 359.2 +/- 200.2 mg/dl). In diabetics, stimulated fibrinolysis following venous occlusion was depressed compared with controls (110.6 +/- 3.9 vs 121.6 +/- 1.9 BAU) (P less than 0.05). No relation of fibrinolytic activity to age, duration of diabetes, obesity, serum triglyceride, HbA1c, or 24 h proteinuria was demonstrated. In the diabetic retinopathy group, the fibrinolytic activity was lower than in the non-retinopathy group. Diabetics with long-standing diabetes (10 years or more) who remained free from retinopathy had significantly increased fibrinolytic activity than the diabetics with short-standing diabetes (less than 10 years) who have developed retinopathy (P less than 0.05). These findings imply a poor fibrinolytic activity, not in all diabetics, but only in those with retinopathy, and this may play a role in the development of diabetic retinopathy.