• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.3
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• pp.395-403
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• 2019

This paper compares the marine engineering courses of two maritime institutions: Mokpo National Maritime University of Korea in the East Asia region and Philippine Merchant Marine Academy in the Southeast Asia region. It shows examines educational marine engineering programs, along with the different divisions and courses at each college. It demonstrates a divergence in methodologies and course offerings to cultivate competitive graduates. The comparative assessment completed is intended to offer broader knowledge on how each institution tackles the requirements of the STCW, and to meet the present and future demands of the maritime industry. Different course offerings are compared along with the units and hours allocated to each subject, and the differences in marine engineering academic and training requirements to graduate. Students must satisfactorily earn 150 units to complete their choice of major. Statistical procedures were used in this assessment and analysis from Excel programs.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.103-105
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• 2011

그림자 페이지테이블(shadow page table)은 MMU 를 가상화 함으로써 게스트 운영체제들이 하드웨어에서 제공하는 물리 메모리를 실제로 사용하는 것처럼 보이도록 하는 기술로 전가상화 지원 ARM 기반 가상머신 모니터인 ViMo 역시 게스트 운영체제간의 메모리 격리를 위해서 그림자 페이지 테이블을 사용한다. 본 논문에서는 그림자 페이지테이블의 성능을 향상시키기 위하여 ViMo에서 사용하는 그림자테이블에 지연 동기화 기법을 추가하는 방법에 대해 설명하고 성능상의 이점을 보인다.

• Proceedings of the Korea Information Processing Society Conference
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• 2024.05a
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• pp.275-276
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• 2024

Cortex-M 프로세서는 가상 메모리를 지원하는 MMU 를 제공하지 않는 대신 메모리 보호 옵션으로 MPU 를 제공한다. MPU 를 사용해 특정 메모리 영역에 대한 접근 권한과 속성을 정의할 수 있고, 이를 이용해 중요한 데이터를 보호하거나 특정 동작을 수행하기 위해 고의로 예외를 발생시킬 수 있다. 본 논문에서는 메모리 보호에 MPU 를 사용한 연구에 대해 조사하였다.

• Journal of KIISE
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• v.42 no.4
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• pp.434-441
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• 2015

Next generation memory technologies, which we denote as 'new memory', have both non-volatile and byte addressable properties. These characteristics are expected to bring changes to the conventional computer system structure. In this paper, we propose a fast boot technique for hybrid main memory architectures that have both new memory and DRAM. The key technique used for fast booting is write-tracking. Write-tracking is used to detect and manage modified data detection and involves setting the kernel region to read-only. This setting is used to trigger intentional faults upon modification requests. As the fault handler can detect the faulting address, write-tracking makes use of the address to manage the modified data. In particular, in our case, we make use of the MMU (Memory Management Unit) translation table. When a write occurs to the boot completed state, write-tracking preserves the original state of the modified address of the kernel region to a particular location, and execution continues. Upon booting, the fast booting process restores the preserved data to the original kernel region allowing rapid system boot-up. We develop the fast booting technique in an actual embedded board equipped with new memory. The boot time is reduced to less than half a second compared to around 15 seconds that is required for the original system.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.4
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• pp.451-460
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• 2014

In this paper, we examined the problem of the structural stability according to the patch load of a rectangular plate that reflects the material properties of A6082-T6 is used primarily for marine plant structure. it applied to the four patch loading shapes, the effect of aspect ratio, a boundary condition and calculated the critical elastic buckling load. Calculating the critical elastic buckling load, During the eigenvalue buckling analysis it is applied to the shell181 as 4 node shell element. when the plate subjected to patch loading compare to the plate under a uniform axial compression load, it is possible observed to occur the different elastic buckling behaviour and it could be confirmed that it is affected significantly on a variable position and type of loadings, such as the effect of the aspect ratio. Also, Critical elastic buckling load according to th patch loading type in simply supported rectangular plate a/b=1.0, ${\gamma}b$=200mm are calculated 67%(Loading type I), 119 %(Loading type II), 76 %(Loading type III), 160 %(Loading type IV), respectively. Loading type I and III could be determined with the strong elastic buckling behavior much more than Loading type II and IV.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.5
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• pp.702-706
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• 1995

A major component(compound A) in the ethylacetate fraction exhibited a strong antimicrobial activity was identified by UV, IR, FABMS and NMR. The compound A showed strong absorbance at 209, 259 and 359nm, indicating a flavonoid ring structure. IR spectrum possessed absorbance of OH at 3400∼3300cm-1, ketone at around 1650cm-1, and aromatic C=C at around 1660cm-1. Molecular weight of the compound A calculated as 478 from the information of m/z 479(M＋H)+ and m/z 477(M-H)+ in the FABMS spectrum. Molecular formula of this compound was found to be C22H22O12 from m/z 479.1220(＋3.1mmu for C22H23O12) of HRFABMS spectrum and from 13C-NMR spectrum. 1H-NMR and 13C-NMR spectra of the compound A revealed aromatic proton and benzene rings. Distortionless enhancement by polarization transfer(DEPT) exhibited that the compound A possessed 10 quaternary carbons and 3 substituted benzene rings including a methoxy group substitution. The compound A was identified as isorhamnetin 3-O-β-glucopyranoside by spectrophotometric methods in conjunction with 1H-1H COSY, 1H-13C COSY and HMBC, which revealed a flavone with OH group at 3, 5, 7, and 4' and methoxy group at 3' positions esterified to glucose.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.6
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• pp.849-855
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• 2011

Emergency batteries on board are used for stairs, pathway lights, and emergency communications during alternator black-out. In addition, there are engine start-up batteries in lifeboats. Typically, these batteries are installed under the Classification Rules. However, Since batteries inside life boats are installed in a confined narrow space, it is difficult to perform regular maintenances. Also, even though there are air vents in the life boat, the temperature inside the life boat often reaches above $65^{\circ}C$, which is much higher than the regulation temperature, $45^{\circ}C$. In this paper, we will summarize the accident of battery explosion occurred in MMU training ship, and possible causes. We will propose preventive measures of battery explosions as well as the revision of the regulation.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1002-1004
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• 2003

A ground-based, C-band full polarimetric mobile Scatterometer system has been developed in Malaysia with collaboration between Malaysian Centre for Remote Sensing (MACRES) and Multimedia University (MMU). The main purpose of this system is to measure and monitor backscattering coefficient, ${\sigma }^0$, for earth terrain such as paddy fields, forest and soil surfaces. This paper describes the preliminary results on radar backscatter measurement from paddy field using the mobile C-band Scatterometer system. The measurement campaign was conducted at Sungai Burung area in April 2003. Real time data were collected using four polarization modes (HH, HV, VV and VH), at various incidence angles ranging from 0$^0$ to 60$^0$. The measurement data show consistent results as compared to other reports, which verify the capability of this Scatterometer system as a useful tool for remote sensing.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.4
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• pp.389-394
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• 2010

This paper describes the conceptual design of mass memory unit for high speed data processing and mass memory management in the STSAT-3 compared to that of STSAT-2. The FPGA directly controls the data receiving from two payloads with the maximum 100Mbps speed and 32Gb mass memory management to satisfy these requirements. We used SRAM-based FPGA from XILINX having fast operating speed and large logic cells. Therefore, the Triple Modular Redundancy(TMR) and configuration memory scrubbing techniques will also be used to protect FPGA from Single Event Upset(SEU) in space.

• IEMEK Journal of Embedded Systems and Applications
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• v.5 no.4
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• pp.225-233
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• 2010

In this paper, we try to improve the performance of the demand paging loader suggested to use the demand paging way that is not based on operating system. The demand paging switching strategy used in the existing operating system can know the recently used pages by running multi-processing. Then, based on it, some page switching strategies have been made for the recently used pages or the frequently demanded pages. However, the strategies based on operating system cannot be applied in single processing that is not based on operating system because any context switching never occur on the single processing. So, this paper is trying to suggest the demand paging switching strategies that can be applied in paging loader running in single process. In the Return-Prediction-Algorithm, we saw the improved performance in the program that the function call occurred frequently in a long distance. And then, in the Most-Frequently-Used-Page-Remain-Algorithm, we saw the improved performance in the program that the references frequently occurred for the particular pages. Likewise, it had an enormous effect on keeping the memory reduction performance by the demand paging and reducing the running time delay at the same time.