• The Journal of Society for e-Business Studies
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• v.8 no.2
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• pp.33-48
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• 2003

Wireless Internet, created through the merging of mobile communication with Internet technology, provides the advantage of mobility, but the restrictions of the mobile environment are deterring it from growing into a mass public service. Of the restricting factors of the wireless environment, narrow memory space creates the disadvantage of not being able to manage resources in mobile devices efficiently Because there is a limit to obtaining sufficient memory space from hardware made with consideration of portability, future devices will need to have a platform design with storage area extended from internal storage to external storage space. In this paper, we present a mobile agent that extends the memory space from only the inside of a mobile device to an external server making it possible to use data by on-line Run-time, and can also manage internal files efficiently. We have designed and implemented a RMS(Resources Management System) as a realization. Devices using the proposed RMS will be able to apply extended processes with the 'Mobile Space Extension' and will be benefited with optimal memory space through efficient internal file management.

• Journal of Korea Society of Industrial Information Systems
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• v.18 no.2
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• pp.27-34
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• 2013

NAND Flash Memory has been used in several devices by low cost and high capacity, and the demand for mass NAND Flash Memory has increased due to the multimedia extension of mobile devices. The JFFS2, NILFS2, and YAFFS2 file systems are used mainly in NAND Flash Memory. In this paper, the performance of Sequential read/write of the 3 file systems are analyzed for the 4 I/O schedulers : CFQ(Complete Fair Queuing) I/O scheduler, NOOP(No Operation) I/O scheduler, Anticipatory I/O scheduler, and Deadline I/O scheduler. In JFFS2 file system, Anticipatory I/O scheduler has the best performance by 8% decreasing speed in writing time and 1.5% decreasing speed in reading time compared to the other I/O scheduler. In YAFFS2 file system, it results are similar to performance in reading and writing for the 4 I/O schedulers. In NILFS2 file system, NOOP I/O scheduler has 2% faster in writing and Deadline I/O scheduler has 6% faster in reading than other I/O schedulers.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.1
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• pp.70-74
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• 2010

As the storage capacity of the flash memories increased portable devices began to store mass amount of multimedia data on flash memory. Therefore, there has been a need for an effective data management scheme by indexing structure. Among many indexing schemes, M-tree is well known for it's suitability for multimedia data with high dimensional matrix space. Since flash memories have writing operation restriction, there is a performance limitation in indexing scheme with frequent write operation. In this paper, a new node split method with reduced write operation for m-tree indexing scheme in flash memory is proposed. According to experiments the proposed method reduced the write operation to about 7% of the original method. The proposed method will effectively construct an indexing structure for multimedia data in flash memories.

• Journal of the Korean Society of Systems Engineering
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• v.11 no.1
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• pp.67-72
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• 2015

It has been tested for SW reliability in order to prevent the SW error during the development of weapons systems. According to a recent report, defects such as memory leak, buffer overflow, and null deference occur usually in the development stage, but also in the mass production stage. Although it is intended to enhance the SW test and evaluation to prevent SW failures in the development stage, the non-functional problems like syntax errors are not completely revised due to the limitation of the schedule and costs. In addition, SW failure rate are usually fluctuated by the operational environment through SW upgrade in contrast with HW. In this paper, we propose a method to increase SW reliability in the mass production stage of Korean weapon systems.

• Journal of the Semiconductor & Display Technology
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• v.22 no.4
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• pp.38-47
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• 2023

Three dimensional (3D) packaging is a next-generation packaging technology that vertically stacks chips such as memory devices. The necessity of 3D packaging is driven by the increasing demand for smaller, high-performance electronic devices (HPC, AI, HBM). Also, it facilitates innovative applications across another fields. With growing demand for high-performance devices, companies of semiconductor fields are trying advanced packaging techniques, including 2.5D and 3D packaging, MR-MUF, and hybrid bonding. These techniques are essential for achieving higher chip integration, but challenges in mass production and fine-pitch bump connectivity persist. Advanced bonding technologies are important for advancing the semiconductor industry. In this review, it was described 3D packaging technologies for chip integration including mass reflow, thermal compression bonding, laser assisted bonding, hybrid bonding.

• Journal of Korean Neurosurgical Society
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• v.60 no.3
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• pp.380-384
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• 2017

Glioblastoma multiforme (GBM) is located most frequently in the cerebral hemispheres. Glioblastoma presenting as an extraaxial mass of cerebellopontine angle (CPA) is very rare in adults. We report a rare case of GBM arising in the CPA. The patient was a 71-year-old female, who complained of progressive gait disturbance and poor memory. Initial magnetic resonance imaging (MRI) revealed a $1.4{\times}1.3cm$ mass in the left CPA, with broad base to the petrous bone, showing homogenous enhancement. Follow-up MRI showed a rapid increase in size of mass ($2.7{\times}2.2cm$) with a necrotic portion. A stereotactic biopsy was done under the guidance of navigation system, and the histopathologic diagnosis was GBM, World Heath Organization grade IV. Further surgical resection was not performed considering her general condition, and the patient underwent concurrent chemotherapy with radiation therapy. Although rare, the possibility of glioblastoma should be included in the differential diagnosis of atypical CPA tumor.

• Journal of Korean Neurosurgical Society
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• v.50 no.5
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• pp.457-459
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• 2011

A rare case of spontaneous subarachnoid hemorrhage from newly developed cerebral aneurysm in glioblastoma patient is presented. A 57-year-old man was presented with headache and memory impairment. On the magnetic resonance image and the magnetic resonance angiography, a large enhancing mass was found at right frontal subcortex and intracranial aneurysm was not found. The mass was removed subtotally and revealed as glioblastoma. He took concurrent PCV chemotherapy and radiation therapy, but the mass recurred one month later after radiotherapy. He was then treated with temozolomide for 7 cycles. Three months after the completion of temozolomide therapy, he suffered from a subarachnoid hemorrhage due to a rupture of a small de novo aneurysm at distal anterior cerebral artery. He underwent an aneurysm clipping and discharged without neurologic complication.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.53.1-53.1
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• 2011

We analyze the halo and galaxy catalogs from the Millennium simulations at redshifts z=0, 0.5, 1 to determine the alignment profiles of cluster galaxies in terms of the matter density correlation coefficient and discuss a cosmological implication our result has for breaking parameter degeneracies. For each selected cluster, we measure the alignment between the major axes of the pseudo inertia tensors from all satellites within cluster's virial radius and from only those satellites within some smaller radius. Then we average the measured values over the similar-mass sample to determine the cluster galaxy alignment profile as a function of top-hat scale difference at each redshift. It is shown that the alignment profile of cluster galaxies is well approximated by a power-law of the nonlinear density correlation coefficient that is independent of the power spectrum normalization and bias factor. The alignment profile of cluster galaxies is found to have higher amplitude and lower power-law index when averaged over the larger-mass sample and to have rather weak redshift-dependence. This result is consistent with the picture that the satellite galaxies retain the memory of the external tidal fields right after merging and infalling into the clusters but they gradually lose the initial alignment tendency as the cluster's relaxation proceeds. Demonstrating that the nonlinear density correlation coefficient varies sensitively with the density parameter and neutrino mass fraction, we discuss a potential power of the cluster galaxy alignment profile as an independent probe of cosmology.

• Journal of Korean Neurosurgical Society
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• v.43 no.2
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• pp.105-108
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• 2008

Cystic glioblastoma multiforme (GBM) is a rare disease. Its exact prevalence has not yet been reported. Also, the mechanism of cyst formation remains to be elucidated. We report a case of GBM with a large peripheral cyst. A 43-year-old woman visited our clinic with a 3-month history of severe headache, memory impairment and general weakness. T1-weighted gadolinium-enhanced magnetic resonance (MR) image revealed a midline enhanced solid mass and bilateral symmetric banana-shaped peripheral cysts. A centrally enhanced mass was measured $2{\times}4$ cm in size and both mass and cysts as $7{\times}7$ cm. Both the frontal lobe and the frontal horn were severely compressed inferiorly and posteriorly. We resected a midline solid tumor and cysts via the bilateral interhemispheric transcortical approach. Histopathologic examination revealed GBM. The patient was subsequently treated with fractionated conventional brain radiation therapy, followed by temozolomide chemotherapy. Eighteen months later, there was no tumor recurrence and no neurological deficits were noted. Our patient showed no tumor recurrence and a long survival at a long follow-up.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.6A
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• pp.794-801
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• 2000

In this paper, the efficient new performance evaluation method for digital communication channels is suggested and verified its efficiency in terms of simulation run-tim for the digital satellite broadcasting satellite TV channel. In order to solve the difficulties of the existing Importance Sampling(IS) Technics, we adopted the discrete probability mass function(PMF) in the new method for estimating the statistical characteristics of received signals from the measured Nth order central moments. From the discrete probability mass function obtained with less number of the received signal than the one required in the IS technic, continuous cumulative probability function and its inverse function are exactly estimated by using interpolation and extrapolation technic. And the overall channel is simplified with encoding block, inner channel performance degra-dation modeing block which is modeled with the Uniform Random Number Generator (URNG) and concatenated Inverse Cummulative Pr bility Distribution function, and decoding block. With the simplified channel model, the overall performance evaluation can be done within a drastically reduced time. The simulation results applied to the nonlinear digital satellite broadcasting TV channel showed the great efficiency of the alogrithm in the sense of computer run time, and demonstrated that the existing problems of IS for the nonlinear satellite channels with coding and M-dimensional memory can be completely solved.