• 대한임베디드공학회논문지
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• 제11권6호
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• pp.353-359
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• 2016

In this paper, we propose a high performance L1 cache structure for the high clock CPU. The proposed cache memory consists of three parts, i.e., a direct-mapped cache to support fast access time, a two-way set associative buffer to reduce miss ratio, and a way-select table. The most recently accessed data is stored in the direct-mapped cache. If a data has a high probability of a repeated reference, when the data is replaced from the direct-mapped cache, the data is stored into the two-way set associative buffer. For the high performance and fast access time, we propose an one way among two ways set associative buffer is selectively accessed based on the way-select table (WST). According to simulation results, access time can be reduced by about 7% and 40% comparing with a direct cache and Intel i7-6700 with two times more space respectively.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권12호
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• pp.4099-4113
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• 2022

In this paper, we propose improved maximum access delay time, noise variance, and power delay profile (PDP) estimation schemes for orthogonal frequency division multiplexing (OFDM) system in multipath fading channels. To this end, we adopt the approximate maximum likelihood (ML) estimation strategy. For the first step, the log-likelihood function (LLF) of the received OFDM symbols is derived by utilizing only the cyclic redundancy induced by cyclic prefix (CP) without additional information. Then, the set of the initial path powers is sub-optimally obtained to maximize the derived LLF. In the second step, we can select a subset of the initial path power set, i.e. the maximum access delay time, so as to maximize the modified LLF. Through numerical simulations, the benefit of the proposed method is verified by comparison with the existing methods in terms of normalized mean square error, erroneous detection, and good detection probabilities.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2013년도 춘계학술발표대회
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• pp.157-158
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• 2013

Data privacy and access control policies in computer clouds are a prime concerns while talking about the sensitive data. Authorized access is ensured with the help of secret keys given to a range of valid users. Granting the role access is a trivial matter but revoking user access is tricky and compute intensive. To revoke a user and making his data access ineffective the data owner has to compute new set of keys for the rest of effective users. This situation is inappropriate where user revocation is a frequent phenomenon. Time based revocation is another way to deal this issue where key for data access expires automatically. This solution rests in a very strong assumption of time determination in advance. In this paper we have proposed a mutable encryption for oblivious data access in cloud storage where the access key becomes ineffective after defined number of threshold by the data owner. The proposed solution adds to its novelty by introducing mutable encryption while accessing the data obliviously.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2008년도 정보통신설비 학술대회
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• pp.556-558
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• 2008

Secure broadcasting is requirement for payment of TV systems, government or company. Hierarchical key management for access control provides efficient key management in those environment. Also, time-bound hierarchical key management technique generates different keys in each time period. In 2004, Tzeng proposed a time-bound cryptgraphic key assignment scheme for access control in a hierarchy and in 2008, Bertino et al proposed an efficient time-bound hierarchical key management scheme for secure broadcasting. Tzeng's scheme and Bertino et al's scheme are organized in different environment and primitive. In this paper, we analysis above two time-bound hierarchical key management scheme.

• 한국응급구조학회지
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• 제24권1호
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• pp.67-76
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• 2020

Purpose: Effective time management, as well as life-saving care, are important in maximizing the prognosis of patients who have sustained major traumas. This study evaluated the appropriateness of emergency medical system (EMS) provider's essential care and how this care impacted on-scene time in patients with major traumas. Methods: This retrospective observational study analyzed the EMS major trauma documents, classified according to the physiological criteria (Glasgow coma scale <14, systolic blood pressure <90mmHg, Respiration rate <10 or >29) in Daejeon, from January, 2015 to December, 2018. Results: Of the 707 major trauma cases, the mean on-scene time was 7.75±4.64 minutes. According to EMS guidelines, essential care accuracy was 67.5% for basic airway, 36.4% for advanced airway, 91.2% for cervical collar, 81.5% for supplemental oxygen, 47.0% for positive pressure ventilation, 19.9% for intravenous access and fluid administration, and 96.0% for external hemorrhage control. Factors affecting on-scene time were positive pressure ventilation (p<.004), and intravenous access and fluid administration (p<.002). Conclusion: Adherence to guidelines was low during advanced airway procedures, positive pressure ventilation, intravenous access, and fluid administration. In addition, the on-scene time was prolonged when the practitioner provided positive pressure ventilation, intravenous access, and fluid administration; however, these durations did not exceed the recommended 10 minutes.

• 한국의상디자인학회지
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• 제11권3호
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• pp.153-162
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• 2009

The purpose of this study was to examine the differences in the service quality evaluation on the skill and expert, the shop facilities and atmosphere, the time and access, and the price and benefit of a nail care shop by age, income, spendings of appearance and a nail care, and a regular nail care. The survey was performed with questionnaires and the subjects were was 240 consumers who used the nail care. The data were analyzed by frequencies, F-test, T-test, Factor Analysis, one way ANOVA. The results of the study were as follows: Service quality evaluation were classified four factors- the price and benefits, the skill and expertness, the facilities and atmosphere, the time and access. There were no statistically significant differences in the price and benefits by age, income, spendings of appearance and a nail care, and a regular nail care, but there were statistically significant differences in the skill and expertness, the facilities and atmosphere, and the time and access. The service quality on the time and access was evaluated as high by the consumer in the 30s, with more income, and with high appearance and nail care spendings. The service quality on the shop facilities and atmosphere was evaluated as high by the consumers with high nail care spending. The consumers with a regular nail care evaluated the service quality on the skill and expertness, the time and access, the shop facilities and atmosphere as high.

• 한국컴퓨터정보학회논문지
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• 제29권9호
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• pp.115-123
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• 2024

본 논문은 MF-TDMA(Multi-Frequency Time Division Multiple Access) 위성네트워크에서 가상할당기반 요구기반 다중접속 기법인 VADAMA(Virtual Allocation Demand Assigned Multiple Access) 기법에서 제어메시지 충돌로 인한 지연시간을 줄이는 방안을 제안한다. 위성 네트워크는 전통적으로 모든 네트워크 전송은 긴 지연시간이 제어메시지로 인해 발생하는 문제가 있었다. 본 연구에서는 가상할당 개념으로 지연시간을 줄인 VADAMA 기법에서 단말의 제어메시지 충돌로 인한 지연시간을 개선하기 위해, 모든 단말을 subnet으로 나눠 순서대로 제어메시지를 전송하도록 하는 VADAMA-PTR(VADAMA Periodic Transfer Request) 제안하였으며, 이를 기존의 DAMA 기법들과 지연시간과 데이터 처리율을 Matlab으로 성능분석하여 성능 향상이 있음을 보였다.

• 한국ITS학회 논문지
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• 제4권1호
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• pp.107-115
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• 2005

For effective IP based service implementation on the wireless network environments, wireless network including the ITS network have to support QoS guaranteed protocol such as a RSVP. RSVP is a resource reservation protocol for Internet environment, and its scalability makes easy to implement RSVP over the various IP transport technologies. But for the If based ITS wireless network environment, RSVP is not suitable, since by its path setup procedure characteristic. In the wireless access network for ITS service, when a mobile node moves to other domain it must perform registration procedure. But the registration procedure is time consuming steps, so if a RSVP session was already established in the previous domain, the RSYP session may be disconnected and the time to re establish a new RSVP session is long enough to cause serious packet loss. In this paper, we propose a pre-path reservation mechanism for applying the RSVP in wireless access networks for ITS. In the pre-path reservation mechanism, the resource reservation procedure occurred during a mobile node's handoff time. An access point in wireless access network performs this procedure when the mobile node attempts handoff The access point executes pre-path reservation procedure as a proxy, since the mobile node does not have IP address until the address allocation procedure is finished in a new domain.

• ETRI Journal
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• 제36권6호
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• pp.988-998
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• 2014

For memory-based big data storage, using hybrid memories consisting of both dynamic random-access memory (DRAM) and non-volatile random-access memories (NVRAMs) is a promising approach. DRAM supports low access time but consumes much energy, whereas NVRAMs have high access time but do not need energy to retain data. In this paper, we propose a new data migration method that can dynamically move data pages into the most appropriate memories to exploit their strengths and alleviate their weaknesses. We predict the access frequency values of the data pages and then measure comprehensively the gains and costs of each placement choice based on these predicted values. Next, we compute the potential benefits of all choices for each candidate page to make page migration decisions. Extensive experiments show that our method improves over the existing ones the access response time by as much as a factor of four, with similar rates of energy consumption.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권6호
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• pp.2781-2800
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• 2016

Emerging attacks aim to access proprietary assets and steal data for business or political motives, such as Operation Aurora and Operation Shady RAT. Skilled Intruders would likely remove their traces on targeted hosts, but their network movements, which are continuously recorded by network devices, cannot be easily eliminated by themselves. However, without complete knowledge about both inbound/outbound and internal traffic, it is difficult for security team to unveil hidden traces of intruders. In this paper, we propose an autonomous anomaly detection system based on behavior profiling and relation mining. The single-hop access profiling model employ a novel linear grouping algorithm PSOLGA to create behavior profiles for each individual server application discovered automatically in historical flow analysis. Besides that, the double-hop access relation model utilizes in-memory graph to mine time-sequenced access relations between different server applications. Using the behavior profiles and relation rules, this approach is able to detect possible anomalies and violations in real-time detection. Finally, the experimental results demonstrate that the designed models are promising in terms of accuracy and computational efficiency.