• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.6
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• pp.855-861
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• 2013

Smartphone is very useful for use in the real life through the improvement of computing power, faster data rate and the variety of applications. On the other hand, using the smartphone has been exposed to a lot of crime. Also, it occurs attempting to delete a data of smartphone memory by anti-forensic tools. In this paper, we investigate and analyze the anti-forensic tools used in the Android smartphone to study the characteristics and techniques of anti-forensic tools. In addition, experiments are performed to validate the availability of anti-forensic tools by the Oxygen Forensic Suite that is a commercial forensic tool.

• Journal of information and communication convergence engineering
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• v.8 no.1
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• pp.40-44
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• 2010

opportunistic spectrum access (OSA) allows unlicensed users to share licensed spectrum in space and time with no or little interference to primary users, with bring new research challenges in MAC design. We propose a cognitive MAC protocol using statistical channel information and selecting appropriate idle channel for transmission. The protocol based on the CSMA/CA, exploits statistics of spectrum usage for decision making on channel access. Idle channel availability, spectrum hole sufficiency and available channel condition will be included in algorithm statistical information. The model include the control channel and data channel, the transmitter negotiates with receiver on transmission parameters through control channel, statistical decision results (successful rate of transmission) from exchanged transmission parameters of control channel should pass the threshold and decide the data transmission with spectrum hole on data channel. A dynamical sensing range as a important parameter introduced to maintain the our protocol performance. The proposed protocol's simulation will show that proposed protocol does improve the throughput performance via traditional opportunistic spectrum access MAC protocol.

• International Journal of Contents
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• v.2 no.2
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• pp.10-16
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• 2006

In this paper, we propose a predictive resource metric region (RMR) based radio resource metric estimation (RRME) mechanism, which utilizes a resource metric mapping function (RMMF), both of which permit efficient inter-working between the physical layer and higher layers for envisaging multimedia service applications over a CDMA communication system platform. The RMR can provide the acceptable resource region where QoS and acceptable link quality can be guaranteed with an achievable resource margin to be utilized in terms of capacity margin, the degree of confidence (DCL) of user, second-order statistics of Eb/Io. With predicted capacity margin and variance, DCL can deliver decision parameters with which an adaptive QoS based admission control can perform well taking capacity and resource availability into account in a dynamic and predictive manner. Combined with advanced techniques such as adaptive modulation or rate control and power control, the proposed mechanism can adjust the conventional stringent link quality information efficiently, and deliver accurate information of the resource availability. Thus, these can guarantee the maximization of resource utilization of multimedia service applications.

• The Journal of Engineering Research
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• v.7 no.1
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• pp.53-60
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• 2005

Community Wireless Networks define the next generation wireless services. Multimedia usages for financial services over community Wireless LAN (WLAN) based mesh networks require link stability. Several new services are being proposed for multimedia over WLANs. Portable Internet Services are implemented by several wireless carriers to proliferate their customer base. However, these services are still expensive and require a central telecom/wireless carrier whose monopoly and preference defines the availability of new services. Our research project identifies the usage of these critical services in public places over the financial services backbone architecture to provide efficient easy-to-use and economical services to their customers and merchants without being dependent on the central wireless carrier. The user connects to the network using his regular WLAN NIC using the Mesh Router/Bridge interconnectivity and obtains the needed multimedia and financial services from the ATM-AP Gateway, In our proposed scenario, the ATN AP-MR use AODV protocol and MR-MC is based on 802.11g/a/b IEEE standard. We use multi path routing protocols for reducing the congestion over a particular route. We demonstrate the results of our simulations and test-bed outcome to evaluate link failure rate and oversubscription factors to eliminate network congestion and non-availability of the critical financial services.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.10
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• pp.102-111
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• 2021

Maintainability is a major design parameter that includes availability as well as reliability in a RAM (reliability, availability, maintainability) analysis, and is an index that must be considered when developing a system. There is a lack of awareness of the importance of predicting and analyzing maintainability; therefore, it is dependent on past-experience data. To improve the utilization rate, maintainability must be managed as a key indicator to meet the user's requirements for failure maintenance time and to reduce life-cycle costs. To improve the maintainability-prediction accuracy in the detailed design stage, we present a maintainability-prediction method that applies Method B of the Military Standardization Handbook (MIL-HDBK-472) Procedure V, as well as a Korean maintainability-prediction software package that reflects the system complexity.

• Journal of Wind Energy
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• v.14 no.3
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• pp.61-68
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• 2023

This paper aims to perform optimal operation and maintenance with an integrated monitoring system for offshore wind platforms. Based on the wind direction and wind speed data of existing wind farms, a monitoring system was established along with weather and weather data to maximize the operational efficiency of wind farms. Compared to wind power on land, offshore wind power is difficult to maintain due to weather, logistics and geographical limitations. Therefore, economic analysis of actual operation and maintenance is essential for large-scale offshore wind farms. In this paper, the availability of offshore wind farms was analyzed by using personnel resources, parts inventory, Crew Transfer Vessel (CTV) and Specialized service Operation Vessel (SOV) etc. before the actual operation and maintenance of wind farms. A comparative analysis was conducted to determine the optimum operating efficiency and economical maintenance costs.

• Journal of Pharmaceutical Investigation
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• v.37 no.4
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• pp.211-216
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• 2007

The bark of Alnus japonica has been used for the treatment of fever, hemorrhage and diarrehea in oriental traditional medicine. Recently, it was revealed that the diarylheptanoids from the bark of Alnus japonica possess anti-inflammatory activity and are expected to be applicable for atopic dermatitis. In this study, oregonin, one of major active components in the bark of Alnus japonica, was developed in the form of semisolid formulations for topical delivery. Oregonin was incorporated into four ointment bases: O/W cream, W/O cream, hydrophilic ointment and lipophilic ointment. Oregonin release from all formulation prepared was evaluated. Franz cell method and immersion method were employed to characterize the release patterns of drug from each formulation based on solvent availability. O/W cream showed a better release profile than the other formulations when evaluated with Franz cell method with an order of O/W cream, hydrophilic ointment, W/O cream and lipophilic ointment. In the immersion method, hydrophilic ointment showed the greatest release rate at times 1 hour exceeding compared to other bases with an order of hydrophilic ointment, O/W cream, W/O cream and lipophilic ointment. Hydrophilicity and solvent availability of formulation seems to significantly influence the release rate of oregonin from ointment bases. In this study, we successfully characterized the oregon in ointment and found that o/w cream is a promising formulation for the topical delivery of oregonin.

• Clinical and Experimental Reproductive Medicine
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• v.15 no.2
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• pp.119-128
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• 1988

It has been suggested that the presence of periovarian adhesions might impair the ovarian response to gonadotropins. Total 136 patients who underwent IVF-ET from February to June 1988(88-1 and 88-2 series) at SNUH were classified into three groups according to total ovarian access score, sum of each ovarian availability, estimated by diagnostic laparoscopy : group I(N=43,0%-50%), group II(N=49, 50%-150%) and group III(N=44, 150%-200%). To evaluate the effects of periovarian adhesions on follicular development in controlled ovarian yperstimulation for IVF-ET, serum E2 levels on the day of hCG dministration (Day 0) and the day after hCG administration (Day+1), the number of ovarian follicles with mean diameter${\geqq}$12mm on Day 0, and the number of oocytes retrieved by transvaginal aspiration were measured and compared among groups. There were no significant differences in age of patients, cancellation rate due to inadequate ovarian response, serum E2 levels, the number of ovarian follicles, the number of oocytes retrieved, and oocytes retrieval rate per follicle. In the same patients(N=31) in group II in whom the difference in ovarian availability between two ovaries is more than 50%, there was also no significant difference in the number of ovarian follicles between them. These data suggest that pelvic adhesions including periovarian adhesions have no adverse effects on the ovarian response to gonadotropins stimulation and the outcome of IVF-ET.

• Journal of Veterinary Clinics
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• v.10 no.1
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• pp.1-10
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• 1993

To investigate the availability of hamster test in assaying the fertilizing capacity of dog sperm and the effect of canine sperm motility on sperm binding and penetration, semen were collected from four dogs(three dogs had been proven to be fertile and one dog to be subfertile during the past two years) and then preserved in BWW(Biggers, Whitten, Whittingham) medium for about 20 hours. The semen were given each different treatment according to the experimental design and coincubated with zona-free hamster ova for 5 hours. The ova were stained by lacmoid and examined under phase contrast microscope to investigate the rates of ova bound with sperm(sperm binding) and ova penetrated by sperm(penetration), and also numbers of both bound and penetrated sperm per ovum. In comparison between fertile dogs and a subfertile dog, the rate of sperm binding was higher in fertile dogs than the subfertile dog(p<0.01, p<0.05). The number of bound sperm per ovum was considerably higher in a fertile dog than the subfertile dog((p<0.01), and also difference of number of the bound sperm was obtained among the fertile dogs(p<0.01, p<0.05). The rate of penetration as well as the number of penetrated sperm per ovum was higher in the fertile dogs than the subfertile dog(p<0.01, p<0.05). In fertile dogs. the canine semen preserved at 4$^{\circ}C$ for 18 to 22 hours showed from 30 to 80% motility at Insemination, however, no difference in hamster test was obtained according to different degree of sperm motility. These results indicated that hamster test would be of avail in assaying the fertilizing capacity of dog sperm.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.5
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• pp.855-866
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• 2023

With the rapid advancement and sophistication of defense weapon systems, the government, military, and the defense industry have conducted various innovative attempts to improve the efficiency of post-logistics support(PLS). The Ministry of Defense has mandated RAM-C(Reliability, Availability, and Maintainability-Cost) analysis as a requirement according to revised Total Life Cycle System Management Code of Practice in May 2022. Especially, for the project budget forecast of new PBL(Performance Based Logistics) business contacts, RAM-C is recognized as an obligatory factor. However, relevant entities have not officially provided guidelines or manuals for RAM-C analysis, and each defense contractor conducts RAM-C analysis with different standards and methods to win PBL-related business contract. Hence, this study aims to contribute to the generalization of the analysis procedure by presenting a cost analysis case based on RAM-C for the supply of military depot maintenance PBL project. This study presents formulas and procedures to determine requirements of military depot maintenance PBL project for repair parts supply. Moreover, a sensitivity analysis was conducted to find the optimal cost/utilization ratio. During the process, a correlation was found between supply delay and total cost of ownership as well as between cost variability and utilization rate. The analysis results are expected to provide an important basis for the conceptualization of the cost analysis for the supply of military depot maintenance PBL project and are capable of proposing the optimal utilization rate in relation to cost.