• Korean Journal of Fisheries and Aquatic Sciences
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• 제39권3호
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• pp.269-277
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• 2006

This study prepared functional oyster hydrolysates using two-step enzymatic hydrolysis and investigated their functional properties. To prepare two-step enzymatic hydrolysates (TSEH), oysters were hydrolyzed using 1% Protamex (PR) at $40^{\circ}C$ and pH 6.0 for 1 hr before sequential treatment with one of the following enzymes for 1 hr: Alcalase (AL), Flavourzyme (FL), Neutrase (NE), pepsin (PE), and trypsin (TR). The PRAL, PRNE and PRTR hydrolysates had significantly greater angiotensin I converting enzyme (ACE) inhibitory activity than did PR and the other TSEHs. Only the antioxidant activity of the PRNE hydrolysate was significantly different (p<0.05), while none of the TSEHs had antimicrobial activity. The oyster hydrolysate prepared by sequential treatment with Protamex and Neutrase (PRNE) had the best ACE inhibitory activity and antioxidant activity, with $IC_{50}$ values of 0.40 and 0.94 mg/mL, respectively. The PRNE hydrolysate was processed through an ultrafiltration (UF) series with molecular weight cut-off (MWCO) membranes of 3, 5, 10, and 30 kDa, and the ACE inhibitory, antioxidant, and antimicrobial activities of the permeates were determined. The permeate through the 3-kDa MWCO membrane had greater ACE inhibitory activity and antioxidant activity than did the other PRNE permeates, with $IC_{50}$ values of 0.11 and 0.40 mg/mL, respectively.

• Elastomers and Composites
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• 제51권2호
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• pp.81-92
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• 2016

1,3-Diphenylguanidine (DPG) is commonly used as a secondary accelerator which not only acts as booster of cure but also activating silanization reaction. The aim of this study is to increase the interaction between silica and rubber by using DPG. In this study, mixing was proceeded in two steps. The T-1 compound is mixed DPG with silica and silane coupling agent in the kneader at high temperature which is named as $1^{st}$ mixing step. T-3 compound is mixed DPG with curatives in the two-roll mill at low temperature which is named as $2^{nd}$ mixing step. The T-2 compound is mixed a half of DPG in $1^{st}$ mixing step and the remainder is mixed in $2^{nd}$ mixing step. Total DPG content was equal for all compounds. When DPG is mixed with silica, silane coupling agent during the $1^{st}$ mixing step, a decrease in cure rate and an increase in scorch time can be seen. This indicates that DPG is adsorbed on the surface of silica. during rubber processing. However, bound rubber content is increased and dynamic properties are improved. These results are due to the highly accelerated silanization reaction. However, there are no significant difference in 100%, 300% modulus.

• Journal of Microbiology and Biotechnology
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• 제19권1호
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• pp.93-98
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• 2009

The thermophilic aerobic digestion (TAD) process is recognized as an effective method for rapid waste activated sludge (WAS) degradation and the deactivation of pathogenic microorganisms. Yet, high energy costs due to heating and aeration have limited the commercialization of economical TAD processes. Previous research on autothermal thermophilic aerobic digestion (ATAD) has already reduced the heating cost. However, only a few studies have focused on reducing the aeration cost. Therefore, this study applied a two-step aeration control strategy to a fill-and-draw mode semicontinuous TAD process. The NADH-dependent fluorescence was monitored throughout the TAD experiment, and the aeration rate shifted according to the fluorescence intensity. As a result, the simple two-step aeration control operation achieved a 20.3% reduction in the total aeration, while maintaining an effective and stable operation. It is also expected that more savings can be achieved with a further reduction of the lower aeration rate or multisegmentation of the aeration rate.

• ETRI Journal
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• 제37권6호
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• pp.1251-1258
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• 2015

We investigate an image recovery method for sparse-view computed tomography (CT) using an iterative shrinkage algorithm based on a second-order approach. The two-step iterative shrinkage-thresholding (TwIST) algorithm including a total variation regularization technique is elucidated to be more robust than other first-order methods; it enables a perfect restoration of an original image even if given only a few projection views of a parallel-beam geometry. We find that the incoherency of a projection system matrix in CT geometry sufficiently satisfies the exact reconstruction principle even when the matrix itself has a large condition number. Image reconstruction from fan-beam CT can be well carried out, but the retrieval performance is very low when compared to a parallel-beam geometry. This is considered to be due to the matrix complexity of the projection geometry. We also evaluate the image retrieval performance of the TwIST algorithm -sing measured projection data.

• Journal of information and communication convergence engineering
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• 제11권4호
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• pp.235-240
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• 2013

Cloud systems are popular computing environment because they can provide easy access to computing resources for users as well as efficient use of resources for companies. The resources of cloud computing are heterogeneous and jobs have various characteristics. One such issue is effective job scheduling. Scheduling in the cloud system may be defined as a multiple criteria decision model. To address this issue, this paper proposes a priority-based two-step job scheduling algorithm. On the first level, jobs are classified based on preference. Resources are dedicated to a job if a deadline failure would cause severe results or critical business losses. In case of only minor discomfort or slight functional impairment, the job is scheduled using a best effort approach. On the second level, jobs are allocated to adequate resources through their priorities that are calculated by the analytic hierarchic process model. We then analyze the proposed algorithm and make a scheduling example to confirm its efficiency.

• Phonetics and Speech Sciences
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• 제3권1호
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• pp.87-94
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• 2011

The decision directed (DD) approach is widely used to determine a priori SNR from noisy speech signals. In conventional speech enhancement systems with a DD approach, a priori SNR is estimated by using only the magnitude components and consequently follows a posteriori SNR with one frame delay. We propose a phase-dependent two-step a priori SNR estimator based on the minimum mean square error (MMSE) in the log-mel spectral domain so that we can consider both magnitude and phase information, and it can overcome the performance degradation caused by one frame delay. From the experimental results, the proposed estimator is shown to improve the output SNR of enhanced speech signals by 2.3 dB compared to the conventional DD approach-based system.

• Journal of the Korean Institute of Navigation
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• 제24권4호
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• pp.299-312
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• 2000

Because shore(ship) to ship(shore) communication service via INMARSAT pay expensive cost, satellite service typically use two stage service that land users dial up LES(Land Earth Station) for sending or receiving message. In order to send and receive message, land users must maintain online state with LES on dedicated line. Also, two stage INMARSAT communication service must consume long time that processes step by step. In case of large company, they have own communication system, but small companys communicate simple messages with only telex. This paper describes the design and implementation of an integrated communication services via INMARSAT-C. This system uses inexpensive INMARSAT-C for transmission between ship and land. Because this system provides web and E-Mail interface, users send and receive messages easily and quickly. This system provides most users with inexpensive and easy communication facilities between ship and land.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.536-539
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• 2004

In this paper, a brief discussion on I-PD position controller design for step motor drive is presented. The proposed method mainly focuses on the robustness property of the controller, which is very important for this type of system in which the variation of external load affects plant parameters. It is considered in this paper that two types of controller design methods namely; Coefficient Diagram Method (CDM), and arbitrary Pole Assignment Method (PAM) are treated and compared them. The control plant chosen for our study is a SM inherently is comprised of some non-linear elements. A the scope of the design method is limited to only linear time invariant systems, the SM modeling is approximated to linear system.

• International Journal of Advanced Culture Technology
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• 제4권4호
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• pp.75-80
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• 2016

The process of extracting external boundary of an object is a very important process for recognizing an object in the image. The proposed extraction method consists of two processes: External Boundary Extraction and Thinning. In the first step, external boundary extraction process separates the region representing the object in the input image. Then, only the pixels adjacent to the background are selected among the pixels constituting the object to construct an outline of the object. The second step, thinning process, simplifies the outline of an object by eliminating unnecessary pixels by examining positions and interconnection relations between the pixels constituting the outline of the object obtained in the previous extraction process. As a result, the simplified external boundary of object results in a higher recognition rate in the next step, the object recognition process.

• International Journal of Reliability and Applications
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• 제2권4호
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• pp.269-280
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• 2001

The objective of this paper is to provide a model for effective implementation of costing RAM management in the design and procurement of production facility considering the system cost-performance trade-off. This research proposes a two-step approach of costing RAM design and test of system RAM for production facility. In Step 1, a static model is proposed to find an initial system configuration to meet the required performance based on system RAM and LCC and analyzes the trade-off relationships between various factors of RAM and LCC. In the second Step, we developed time and failure truncated models for system reliability test and analysis. For the computational purpose, we developed computer programs and have shown the sample results. By the sample test run, the proposed model has shown the possibilities to provide a good method to analyze system performance evaluation for both design and operational phase, This model can be applied to a wide variety of systems not only for costing RAM of the production facilities but also for the other kinds of equipment.