• 정보저장시스템학회논문집
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• 제2권1호
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• pp.32-37
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• 2006

The recording density of a hard disk drive(HDD) has been increased so rapidly that the storage capacity of a commercial HDD for the personal computer already reaches several hundred giga-bytes recently. Many technologies related to the HDD, such as servo, media, actuator dynamics, thermo and fluid dynamics, etc. must be developed together to realize higher recording density. Especially, airflow inside the HDD cavity has been concerned as the rotational speed of the disk increases. Typical problem due to the airflow is the off-track vibration of a head stack assembly(HSA) as the airflow collides with the E-block, suspensions, and sliders, i.e., the flow induced vibration(FIV). This problem is one of the most significant sources of the track mis-registration(TMR) so that it must be resolved. In this study, disk damper shape is modified to minimize the influence of airflow on the HSA. Modified disk dampers, which change the flow field of the inside cavity of a HDD, show good effects not only on the disk vibration but also on the off-track vibration of a HSA. Vibrations of E-block and slider have been measured with LDV and the airflow field inside the HDD cavity has been analyzed with commercial CFD program to verify these effects.

• 한국수산과학회지
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• 제55권4호
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• pp.425-430
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• 2022

This study was designed to verify the shelf-life of a freeze dried-block type of convenience food for rockfish Sebastes schlegeli seaweed soup product stored at different storing temperatures (25, 35, and 45℃) for 5 months. The polyunsaturated:saturated fatty acid ratio of the product stored at 25℃ was higher than that of products stored at 35℃ and 45℃ for 5 months. The colorimetric assessment indicated a noticeable decrease in the brightness of product color after 5months of storage at 35℃ and 45℃. Increased storage temperature and time negatively affected the product color. The products stored at 35℃ and/or 45℃ for more than 3 months tended to be more yellowish-red in color than those stored at 25℃ for shorter periods. No disease-causing microorganisms, including Escherichia coli and Staphylococcus aureus, posing health hazards to the human, were detected on food safety evaluation, regardless of storage conditions. Based on food visual shelf life simulator the shelf life of the rockfish seaweed soup was estimated approximately 22 months, considering the data from yellowness the safety factor of 0.7.

• International journal of advanced smart convergence
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• 제12권4호
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• pp.237-245
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• 2023

In the cloud service, system resource such as CPU, memory, I/O bandwidth are shared among multiple users. Particularly, in Linux containers environment, I/O bandwidth is distributed in proportion to the weight of each container through the BFQ I/O scheduler. However, since the I/O scheduler can only be applied to conventional block storage devices, it cannot be applied to Zoned Namespace(ZNS) SSD, a new storage interface that has been recently studied. To overcome this limitation, in this paper, we implemented a weighted proportional I/O bandwidth sharing scheme for ZNS SSDs in dm-zoned, which emulates conventional block storage using ZNS SSDs. Each user receives a different amount of budget, which is required to process the user's I/O requests based on the user's weight. If the budget is exhausted I/O requests cannot be processed and requests are queued until the budget replenished. Each budget refill period, the budget is replenished based on the user's weight. In the experiment, as a result, we can confirm that the I/O bandwidth can be distributed on their weight as we expected.

• Journal of Multimedia Information System
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• 제4권1호
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• pp.19-26
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• 2017

The compression of video for both full HD and UHD requires the inclusion of extra vertical lines to every video frame, named as the DTV essential hidden area (DEHA), for the effective functioning of the MPEG-2/4/H encoder, stream, and decoder. However, while the encoding/decoding process is dependent on the DEHA, the DEHA is conventionally viewed as a redundancy in terms of channel utilization or storage efficiency. This paper proposes a block mode DEHA method to more effectively utilize the DEHA. Partitioning video block images and then evenly filling the representative DEHA macroblocks with the average DC coefficient of the active video macroblock can minimize the amount of DEHA data entering the compressed video stream. Theoretically, this process results in smaller DEHA data entering the video stream. Experimental testing of the proposed block mode DEHA method revealed a slight improvement in the quality of the active video. Outside of this technological improvement to video quality, the attractiveness of the proposed DEHA method is also heightened by the ease that it can be implemented with existing video encoders.

• 대한임베디드공학회논문지
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• 제14권2호
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• pp.97-102
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• 2019

Multi-queue I/O block layer has been recently employed in Linux kernel to support fast storage devices such as NVMe SSDs, but it lacks differentiated I/O services yet. In this paper, we propose an I/O scheduling scheme that can improve the user responsiveness of foreground processes, which are closely related to user satisfaction. To this end, we redesign the existing multi-queue block layer to classify the I/O requests from foreground processes and schedule them by exploiting the feature of NVMe interface. Experimental results show that latency and launch time of the foreground processes have been significantly improved compared to original Linux kernel.

• 국제초고층학회논문집
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• 제12권1호
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• pp.19-33
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• 2023

Air Rights techniques, including floor-area ratio (FAR) transfers, FAR bonuses, and FAR storage, have been widely applied among skyscraper constructions in New York City for profit maximization goals. Since 1916, air rights regulations in New York zoning system have been revised and improved over the years to cater the urban development needs of different periods, and they also result in typical skyscraper block typologies. This research firstly performed spatial overlay analysis to reveal the spatial correlation between skyscraper blocks and air rights application blocks; secondly, Spacematrix parameters and cluster analysis are applied to divide the skyscraper urban block of New York City into four categories. Compared with air rights application data, the research attempts to illustrate how various air rights techniques have acted on the formation and evolution of skyscraper block typologies in the pre-1916, 1916-1961, 1961-2010, and 2010-present periods respectively, in order to reveal the relationship between public policies and urban morphology in a broader sense and also provide references for policy making in future.

• 한국조경학회지
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• 제34권5호
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• pp.76-83
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• 2006

The purpose of this study was to investigate the performance of porous grass block. For the investigation, Festuca arundinacea and Zoysia japonica 'Zenith' were planted, and the volume of evapotranspiration and remains were examined based on different materials in the water tank in the experiment of Festuca arundinacea, the volume of water storage of treatment with perlite ($10.84{\iota}/m^2$) was higher than that with drainage ($7l/m^2$). The difference between the two was $3.84/m^2$. The drainage treatment without water storage capacity showed the higher degree of dryness in turf grass. The volume of evapo-transpiration of treatment with perlite was the highest (21.57mm/week). The volume of evapotranspiration of treatment with sand was 19.57mm/week, and with treatment with drainage was 18.24mm/week. Based on the measured volume of daily evapotranspiration of $2.60{\sim}3.08mm\;d^{-1}$, it was determined that the unit with water storage capacity would store water of one to two days usage compared to unite without such storage capacity. In the experiment of Zoysia japonica 'Zenith', the volume of water storage of treatment with perlite was $10.77l/m^2$ which was similar to the former experiment. The volume of evapotranspiration of treatment with perlite and sand were 21.64mm/week and 20.64mm/week, respectively. In case of airtight water tank, the volume was measured as 22.06mm/week. Each treatment has no notable difference in the volume of evapotranspiration. In conclusion, from the investigation in this study, porous grass block with water tank was found to be effective in plant growth under low irrigation. As the ecological area ratio and vegetated porous pavement have became more emphasized, additional study of rain infiltration and reservoir effect are needed in the future.

• Preventive Nutrition and Food Science
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• 제20권3호
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• pp.169-175
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• 2015

Shinseoncho and kale were made into green vegetable juices by building block [shinsenocho branch (SB), shinsenocho leaf (SL), kale branch (KB), and kale leaf (KL)]. Fluctuations in their phenolic contents and antioxidant capacities were analyzed during refrigerated storage at $4^{\circ}C$ for 28 days. Total polyphenolic contents of leaf parts showed a decreasing tendency after 4 days (SL) or 7 days (KL), whereas branch parts showed fluctuating values during the entire storage period. The 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging capacity was rapidly decreased in SB and in SL at 28 days (P<0.001), whereas KL showed a slightly increasing tendency after 14 days. For the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity, SL showed a sharp fall at 28 days (P<0.001), and KL showed a decreasing tendency after 14 days (P<0.001). SB showed a steady decrease during the entire storage period and KB indicated a nearly zero (0.97%) at 28 days. Pearson's coefficients for the correlation between antioxidant capacities measured by the ABTS and DPPH assays, and the total polyphenolic contents were determined. The results showed that the ABTS assay (r=0.934, P<0.001) was more strongly positively correlated with the total phenolic contents than the DPPH assay (r=0.630, P<0.001). In conclusion, when considering all building blocks, green vegetable juices, including kale and shinseoncho may have kept antioxidant capacities for up to 14 days under refrigeration, and the ABTS assay better reflects a positive correlation with the total phenolic contents when compared to the DPPH assay.

• 한국물환경학회지
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• 제34권3호
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• pp.293-300
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• 2018

Ihe purpose of this study is to evaluate the effects the storage type of permeable concrete block paving (ST-PCBP) have on runoff reduction and infiltration increasement at Andong Maskdance Festival Square. This was accomplished using the NRCS-curve number method over the last 10 years. Two different scenarios were developed in this study for low impact development (LID) design. For the $1^{st}$ scenario, the walking path and parking lot were install using the ST-PCBP and runoff from the inline skating rink ($3,808m^2$) and lawn ($11,191m^2$) were routed to the ST-PCBP, but the rooftop runoff flowed into the storm water drainage system. For the $2^{nd}$ scenario, one of the non-structural BMPs, disconnected impervious surface (DIS), was applied so additional runoff from rooftop would enter the ST-PCBP. It was determined that ST-PCBP could significantly reduce surface runoff from the study area and increase infiltration with 71% and 88% of surface runoff reduction and 151% and 215% of infiltration increasement for scenarios 1 and 2, respectively. The effect of LID in the $2^{nd}$ scenario was better than the $1^{st}$ scenario, therefore DIS in conjunction with ST-PCBP could be a more cost-effective LID application.

• 한국건축시공학회지
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• 제24권2호
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• pp.227-238
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• 2024

본 연구에서는 최근 이상기후로 인해 양극화된 기후 패턴으로 인한 침수 피해가 증가하고 있으며, 그 해결책이 빗물 침투저류블록이라고 설명하고 있다. 또한, 기존 프로그램의 한계점으로 드론 기술과 결합된 새로운 기능이 필요함을 제안하며, 저류조 기능을 가진 빗물침투저류블록의 최적 설치 장소 선정을 목표로 하는 침수·범람 시뮬레이션 기술 개발에 대한 실험 및 평가를 진행한다. 실제 빗물침투저류블록이 실시공된 지역을 대상으로 평가를 진행하였으며, DEM과 DSM을 통한 기존 프로그램과의 비교, 침수·범람 시뮬레이션 프로그램의 실현장 적용성 검토의 2개 항목을 통해 평가를 진행하였으며, 그 결과, 침수·범람 시뮬레이션 프로그램의 실무에 적용함으로써 빗물침투저류블록의 설치 시 최적지 선정을 위한 의사결정 도구로 활용할 수 있다는 것을 확인하였다.