• Journal of Korea Game Society
• /
• v.17 no.3
• /
• pp.53-62
• /
• 2017

VR content manipulation equipment is not easy for individuals to access because it requires high prices. Especially, in the case of a system for tracking the motion of the user among the VR contents, a separate optical sensor device using an infrared camera is generally used. The disadvantage of the optical sensor equipment is that the measurable range is dependent on the measurement direction when tracking the rotation motion when using only a single device. In order to solve the above problems, this paper shows that the inertial sensor of the smartphone, which is generally owned by the public, can track the rotational motion of the user regardless of the measurement direction . The system using the LeapMotion is used as the reference system, and the system using the smart phone is defined as the evaluation system, and the usability of the evaluation system is verified by comparing the user satisfaction of the two systems.

• Journal of the Korea Society for Simulation
• /
• v.25 no.1
• /
• pp.35-43
• /
• 2016

Increasing the proportion of an embedded system in automotive industry, test methods for evaluation and fault detection of the embedded system have been researched. HILS is a test method that is used in the development and test of complex real-time embedded systems. In this study, we defined the HILS method of the ECU, one of the embedded systems used in automobiles. Our method is to create a test model that can provide a virtual vehicle environment to the ECU on the basis of the actual vehicle data. The test model has reference information that can transmit the sensor signal and CAN Message into the ECU from HILS tester. In this study, the HILS can detect faults of the target ECU.

• The KIPS Transactions:PartC
• /
• v.11C no.7 s.96
• /
• pp.937-950
• /
• 2004

In this paper, we present the design and implementation of new execution environment named Customizable Architecture for Flexible Execution Environment(CAFEs) that supports the mechanism of protocol customization and service referencing. We introduce a new concept as micro protocols and active services to enhance software reusability. Micro protocol represents a specific algorithm or functionality of existing network protocol and the active service is in charge of binding legacy application and releasing the active network oriented services. The pro-posed active network execution environment is made up of three parts, virtual network system, protocol and service manager, event engine. First, the virtual network system is used to connect each active nodes using virtual network channels which are based on multiple existing protocol layers. Second, the protocol and service manager is responsible for composing micro protocols and active services to develop new network proto-col and service easily. Finally, the event engine is used to detect the automatic transition of system components using event delegation model. To verify the CAFTs, we have an experiment about the delivery of web contents which are suitable for the user's terminals in the wireless Internet environment. As a result. we are able to obtain the availability of developed execution environment.

• Journal of KIISE
• /
• v.42 no.9
• /
• pp.1071-1077
• /
• 2015

In this paper, we adopt PCM (phase-change memory) as a virtual memory swap device and present a new page replacement policy that considers the characteristics of PCM. Specifically, we aim to reduce the write traffic to PCM by considering the dirtiness of pages when making a replacement decision. The proposed policy tracks the dirtiness of a page at the granularity of a sub-page and replaces the least dirty page among the pages not recently used. Experimental results show that the proposed policy reduces the amount of data written to PCM by 22.9% on average and up to 73.7% compared to CLOCK. It also extends the lifespan of PCM by 49.0% and reduces the energy consumption of PCM by 3.0% on average.

• Journal of the Korea Convergence Society
• /
• v.12 no.7
• /
• pp.45-51
• /
• 2021

In accordance with the rapid non-face-to-face environment and mobile first strategy, the explosive increase and creation of many structured/unstructured data every year demands new decision making and services using big data in all fields. However, there have been few reference cases of using the Hadoop Ecosystem, which uses the rapidly increasing big data every year to collect and load big data into a standard platform that can be applied in a practical environment, and then store and process well-established big data in a relational database. Therefore, in this study, after collecting unstructured data searched by keywords from social network services based on Hadoop 2.0 through three virtual machine servers in the Spring Framework environment, the collected unstructured data is loaded into Hadoop Distributed File System and HBase based on the loaded unstructured data, it was designed and implemented to store standardized big data in a relational database using a morpheme analyzer. In the future, research on clustering and classification and analysis using machine learning using Hive or Mahout for deep data analysis should be continued.

• Spatial Information Research
• /
• v.16 no.2
• /
• pp.157-171
• /
• 2008

With emerging technologies on wireless networks and mobile computing environment, a number of researches have been carried out for ubiquitous computing. An important functional requirement of ubiquitous computing is to handle location data with ease. With the increase of accidents in large complex buildings. move attention is being paid to indoor spaces and evacuation. However, most currently used evacuation-related applications are simulation based on hypothetical data. Also, since they use non-georeferenced CAD data, it is not easy to integrate them with indoor positioning devices. With the recent progress of indoor positioning systems, the simulators can be enhanced to real-time evacuation systems. As a preliminary stage to make such systems possible, this study proposes using a georeferenced data and evacuation simulation. This study used GIS data and Cellular Automata theory an the algorithm for the movement of the evacuee.

• KIPS Transactions on Computer and Communication Systems
• /
• v.3 no.11
• /
• pp.409-418
• /
• 2014

The amount of data located in storage servers has dramatically increased with the growth in cloud and social networking services. Storage systems with very large capacities may suffer from poor reliability and long latency, problems which can be addressed by the use of a hybrid disk, in which mechanical and flash memory storage are combined. The Linux-based SSD(solid-state disk) uses a caching technique based on the DM-cache utility. We assess the limitations of DM-cache by evaluating its performance in diverse environments, and identify problems with the caching policy that it operates in response to various commands. This policy is effective in reducing latency when Linux is running in native mode; but when Linux is installed as a guest operating systems on a virtual machine, the overhead incurred by caching actually reduces performance.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.22 no.6
• /
• pp.57-62
• /
• 2022

Recently, fast storage media such as phage-change memory (PCM) emerge, and memory management policies for slow disk storage need to be revisited. In this paper, we propose a new page replacement policy that makes use of PCM as a swap device of virtual memory systems. The proposed policy aims at reducing write traffic to the swap device as well as reducing the number of page faults pursued by traditional page replacement policies. This is because a write operation in PCM is slow and PCM has limited write endurances. Specifically, the proposed policy focuses on the reduction of page faults when the memory load of the system is high, but it aims at reducing write traffic to storage when free memory space is sufficient. Simulation experiments with various memory reference traces show that the proposed policy reduces write traffic to PCM without performance degradations.

• Journal of KIISE:Computing Practices and Letters
• /
• v.16 no.8
• /
• pp.825-836
• /
• 2010

The advancement of electronic records brought great changes of the records management system. One of the biggest changes is the transition from passive to automatic management system, which manages massive records more efficiently. The integrated Rule-Oriented Data System (iRODS) is a rule-oriented grid system S/W which provides an infrastructure for building massive archive through virtualization. It also allows to define rules for data distribution and back-up. Therefore, iRODS is an ideal tool to build an electronic record management system that manages electronic records automatically. In this paper we describe the issues related to design and implementation of the electronic record management system using iRODS. We also propose a system that serves automatic processing of distribution and back-up of records according to their types by defining iRODS rules. It also provides functions to store and retrieve metadata using iRODS Catalog (iCAT) Database.

• Journal of KIISE:Software and Applications
• /
• v.34 no.9
• /
• pp.828-847
• /
• 2007

In this paper we propose a formal data model of an object-based thesaurus system supporting multi-dimensional facets. According to facets reflecting on respective user perspectives, it supports systematic construction, browsing, navigating and referencing of thesauri. Unlike other faceted thesaurus systems, it systematically manages its complexity by appropriately ing sophisticated conceptual structure through visualized browsing and navigation as well as construction. The browsing and navigation is performed by dynamically generating multi-dimensional virtual thesaurus hierarchies called "faceted thesaurus hierarchies." The hierarchies are automatically constructed by combining facets, each representing a dimension of view. Such automatic construction may make it possible the flexible extension of thesauri for they can be easily upgraded by pure insertion or deletion of facets. With a well defined set of self-referential queries, the thesauri can also be effectively referenced from multiple view points since they are structured by appropriately interpreting the semantics of instances based on facets. In this paper, we first formalize the underlying model and then implement its prototype to demonstrate its feasibility.