• Journal of Computing Science and Engineering
• /
• v.4 no.3
• /
• pp.189-206
• /
• 2010

It is generally accepted that dynamic voltage scaling (DVS) is one of the most effective techniques of energy minimization for real-time applications in embedded system design. The effectiveness comes from the fact that the amount of energy consumption is quadractically proportional to the voltage applied to the processor. The penalty is the execution delay, which is linearly and inversely proportional to the voltage. According to the granularity of tasks to which voltage scaling is applied, the DVS problem is divided into two subproblems: inter-task DVS problem, in which the determination of the voltage is carried out on a task-by-task basis and the voltage assigned to the task is unchanged during the whole execution of the task, and intra-task DVS problem, in which the operating voltage of a task is dynamically adjusted according to the execution behavior to reflect the changes of the required number of cycles to finish the task before the deadline. Frequent voltage transitions may cause an adverse effect on energy minimization due to the increase of the overhead of transition time and energy. In addition, DVS needs to be carefully applied so that the dynamically varying chip temperature should not exceed a certain threshold because a drastic increase of chip temperature is highly likely to cause system function failure. This paper reviews representative works on the theoretical solutions to DVS problems regarding inter-task DVS, intra-task DVS, voltage transition, and thermal-aware DVS.

• Journal of Institute of Control, Robotics and Systems
• /
• v.12 no.10
• /
• pp.968-974
• /
• 2006

We are moving into the era of ubiquitous computing. Ubiquitous Sensor Network (USN) is a base of such computing paradigm, where recognizing the identification and the position of objects is important. For the object identification, RFID tags are commonly used. For the object positioning, use of sensors such as laser and ultrasonic scanners is popular. Recently, there have been a few attempts to apply RFID technology in robot localization by replacing the sensors with RFID readers to achieve simpler and unified USN settings. However, RFID does not provide enough sensing accuracy for some USN applications such as robot navigation, mainly because of its inaccuracy in distance measurements. In this paper, we describe our approach on achieving accurate navigation using RFID. We solely rely on RFID mechanism for the localization by providing coordinate information through RFID tag installed floors. With the accurate positional information stored in the RFID tag, we complement coordinate errors accumulated during the wheel based robot navigation. We especially focus on how to distribute RFID tags (tag pattern) and how many to place (tag granularity) on the RFID tag-floor. To determine efficient tag granularities and tag patterns, we developed a simulation program. We define the error in navigation and use it to compare the effectiveness of the navigation. We analyze the simulation results to determine the efficient granularities and tag arrangement patterns that can improve the effectiveness of RFID navigation in general.

• Korean Journal of Veterinary Pathology
• /
• v.2 no.2
• /
• pp.147-151
• /
• 1998

A five-month old female Great Dane with a history of depression and convulsion was submitted to the Pathology and Diagnosis Reference Division of National Veterinary Research and Quarantine service. The dog had ingested concentrated antifreeze and died 12 days after the sudden onset of clinical signs. Main gross lesion was limited to swollen kidneys with diffusely fine granularity on the cut surface. Principle microscopic lesions were focused on the kidneys including dilated Bowman's space, thickened glomerular basement membrane, many light yellowish crystals, and proteinaceous casts in some tubules. Some neutrophils and lymphocytes were focally infiltrated in interstitium of the cortex and medulla. Crystals were angular or quite irregular in shape and arranged in sheave or rosette form. Under polarized light, the crystals were birefringent, which is typical of calcium oxalate crystals. Crystals were more concentrated in the cortex than in the medulla. A few crystals were also observed in the small blood vessels of the brain. Based upon the history of ingestion of antifreeze and the identification of calcium oxalate crystals in the tissue sections of the kidney and brain, this case was diagnosed as ethylene glycol toxicosis in a dog.

• The Transactions of the Korea Information Processing Society
• /
• v.7 no.1
• /
• pp.126-134
• /
• 2000

Version control is an application to maintain consistency between different instances of the same document allowing operations such as navigation, differencing, and merging. Most version control systems, however, lack the support of functionality for cooperative writing environment, such as to represent and store the history of the actions of different individuals, to effectively differentiate and merge the individual actions including the text object, and to manage different access privileges for different granularity and individuals. With the help of Activity IDentification (AID) tag and its unique addressing scheme proposed in this paper, differencing and merging become simple and effective. Access and role control is improved by associating the access right table and role assignment in AID scheme also eliminates the requirements for large storage capacity for version information maintenance.

• Resources Recycling
• /
• v.16 no.5
• /
• pp.13-18
• /
• 2007

The recycled aggregates produced from waste concrete by crushing and granularity adjusting processes only can't be used for structural aggregates because they display low density and high abrasion rate by including lots of mortar and cement paste. However, the recycled aggregates include a lot of aggregates for concrete. Using the heavy medium separation method that is one of the specific gravity separation methods, about 45% of the waste concrete could be converted to the recycled aggregates.

• Journal of the Optical Society of Korea
• /
• v.20 no.6
• /
• pp.704-715
• /
• 2016

In this paper, we explore a low-complex bandwidth allocation (BA) scheme with multi-level service guarantees in VLC-OFDM systems. Effective capacity theory, which evaluates wireless channel capacity from a novel view, is utilized to model the system capacity under delay QoS constraints of the link layer. Since intensity modulation of light is used in the system, problems caused by frequency selectivity can be neglected. Then, the BA problem can be formulated as an integer programming problem and it is further relaxed and transformed into a concave one. Lagrangian formulation is used to reformulate the concave problem. Considering the inefficiency of traditional gradient-based schemes and the demand for distributed implementation in local area networks, we localize the global parameters and propose a quasi-distributed quadratic allocation algorithm to provide two-level service guarantees, the first level is QoS oriented, and the second level is QoE oriented. Simulations have shown the efficient performance of the proposed algorithm. The users with more stringent QoS requirements require more subcarriers to guarantee their statistical delay QoS requirements. We also analyze the effect of subcarrier granularity on the aggregate effective capacity via simulations.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• v.2
• /
• pp.77-82
• /
• 2006

Integrity plays a fundamental role in the feasibility of 'liability critical' applications. Road charging, e.g. road tolling in urban zones or on highways, represents a series of liability critical applications where a guarantee in integrity could be a true enabler: being the mechanism that prevents the incorrect charging of users and enabling the advancement of these applications using GNSS such as Galileo and EGNOS that provide integrity mechanisms. However, the integrity of the end user position is not guaranteed by the EGNOS and Galileo integrity services alone as provided. Algorithms have been developed to supply a guarantee on the performance attainable at the user level through the provision of a horizontal protection level that responds to local user conditions such as multipath or interference. In addition, an application has been developed that implements road charging mechanisms based on the availability of user-level integrity. Results obtained show that the user-level integrity algorithms provided the required level of integrity guarantee and granularity of the horizontal protection levels necessary for executing urban and rural (highway) road charging. In addition, the road charging application developed shows that the current application domain requirements can be met through the provision of guaranteed integrity and that further reductions in the horizontal protection levels along with increased signal availability will enable future road charging modalities.

• The Transactions of the Korea Information Processing Society
• /
• v.6 no.5
• /
• pp.1153-1165
• /
• 1999

In various fields of information technology, it is growing up the needs about dynamic content management systems to store and manage SGML(Standard Generalized Markup language) documents in a database system. In this paper, we consider the issue of storing SGML documents that having complex hierarchical structure into a database system, and then propose a data model based on ODMG(Object Database Management Group) object model in order to store SGML documents without loss of information. Because the proposed data model reflects physical element structure and logical entity structure of SGML documents, it is able to store the SGML document in a database system at the system at the element- level granularity without any information loss. And also the proposed data model can be adapted among ODMG-compliant object database management systems. Finally, we will discuss on the implementation details of SGML repository system supports the functionality of automatic database schema creation for any DTD(Document Type Definition0, the functionality of storing the SGML document, the functionality of dynamic document assembly from stored database objects to SGML document, and the functionality of indexing and searching for database objects.

• Journal of Korean Institute of Industrial Engineers
• /
• v.27 no.2
• /
• pp.203-213
• /
• 2001

The image and impression characteristics of the consumer electronic products have become an important factor in purchasing decisions. This study aims to analyze and interpret the image and impression characteristics based on the consumer preference survey. The survey consisted of two parts. First part was to measure the predetermined 52 design variables that can represent the design variables of the products. In the second part, 60 subjects were requested to evaluate 36 audio/video electronic products on 25 different image attributes such as luxuriousness, attractiveness, and granularity. In this study, empirical data from the survey were analyzed through various multivariate analysis and ANOVA analysis. Additionally, this study suggested a statistical procedure that can be applied to select and/or screen critical design variables. It is expected that the results of this study can provide practical information to the designers of consumer electronic products.

• Korean Journal of Pharmacognosy
• /
• v.28 no.4
• /
• pp.280-285
• /
• 1997

Pectenotoxin 2 (PTX2), isolated from marine sponges, was examined for its hepatotoxic potential using male ICR mice. PTX2 $(20\;or\;100\;{\mu}g/kg/day,\;ip)$ was administered to mice repeatedly for one or two week. Histopathological examination revealed an increase in granularity in the liver from the mice treated with PTX2. PTX2 did not alter the parameters for hepatotoxicity and nephrotoxicity such as sorbitol dehydrogenase (SDH), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and blood urea nitrogen (BUN). Cytochrome P-450, cytochrome $b_5$, or NADPH cytochrome c reductase was net changed by repeated administration of PTX2. Hepatic microsomal activity of p-nitroanisole O-demethylase, but not aminopyrine N-demethylase, was slightly depressed by PTX2 administerd repeatedly $(100\;{\mu}g/kg/day,\;ip)$ fur 2 weeks. The toxicity of PTX2 $(200\;{\mu}g/kg/day,\;ip)$ was determined in mice pretreated with a metabolic inducer or inhibitor such as phenobarbital, 3-methyl-cholanthrene, $CoCl_2$, or SKF 525-A. Significant alterations in lethality and hepatotoxicity of PTX2 were observed in mice pretreated with a metabolic modulator. The results suggest that liver seems to be the target organ for PTX2 toxicity and also that induction of the PTX2 toxicity may be associated with hepatic drug metabolizing activity.