• The Journal of Society for e-Business Studies
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• v.7 no.2
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• pp.157-171
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• 2002

We want to find a timestamping method which improves efficient performance and have high-level security to send secured messages in the digital signature and the law of e-commerces. Our paper shows a H-binary tree of time stamp to use a time stamp protocol with high security and performance in the packets of sending messages. We implement and analyze the protocols, show to compare with previous RSA methods. Our proposed protocol has O(log n) time complexity and high-performance.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10c
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• pp.589-591
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• 2002

시점확인 서비스(Time-Stamping Service)를 위한 프로토콜인 Time-Stamp protocol(TSP)를 구현하는데 필요한 기능들을 SDK로 구현하였다. 어떤 데이터가 특정 시점 이전에 존재했음을 증명하기 위해 Time-Stamp token을 발행하는 시점확인 서비스는 전자공중, 전자상거래, DVCS 등 여러 보안과 관련된 응용서비스에서 필요한 모듈이다. 본 논문에서는 시점확인 서비스를 위한 time-stamp protocol을 설명하고, TSP SDK 구현 내용, SDK를 시험하기 위한 테스트베드 및 SDK 구현시 참고사항을 서술한다.

• Journal of the Korea Society of Computer and Information
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• v.5 no.3
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• pp.126-131
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• 2000

Through many users employ TCP of which the performance has been proved in Internet, but many papers Proposed to improve TCP performance according to varying network architecture. In Particular, BWDP(bandwidth-delay Product) grew larger because of the increasing delay in satellite link and the network's speed-up. To consider these increased bandwidth-delay product, it is suggested that TCP options include Window Scale option. TimeStamp option, and PAWS. Because TCP window size should be commonly high in the network with these increased bandwidth-delay product, the multiple decrease and linear increase scheme of current TCP would cause underflow and instability within network. Then TCP performance is reduced as a result. Thus, to improve TCP congestion control algorithm in the network which has large sized window, this paper proposes the congestion control scheme that controls window size by using TimeStamp option.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.5
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• pp.199-204
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• 2000

This paper presents new approaches for the calculation for the calculation of each user's wheeling prices based on the economic analysis method with focus on the postage stamp rule. The suggested postage stamp rules can overcome the following problems embedded in the conventional accounting-costs-based methods such as the volatileness of wheeling prices depending deprieciation methods, emerging the wheeling free-riders due to the difference between accounting life-time and technical life-time, price discrimination between firm and non-firm network users, etc. To solve these problems we suggest new postage stamp rules employing capital recovery factor for investment costs treatment and applying technical life-time. Furthermore, we have suggested a new formulation for non-firm wheeling users based on the wheeling energies. In the case study, the results of suggested postage stamp methodologies are compared with those of conventional approaches.

• The KIPS Transactions:PartC
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• v.9C no.6
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• pp.817-822
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• 2002

We want to find a timestamping method which improves efficient performance and have high-level security to send secured messages in the digital signature and the law of e-commerces. Our paper shows a H-binary tree of time stamp to use a time stamp protocol with high suity and performance in the packets of sending messages. We implement and analyze the protocols, show to compare with previous RSA methods. Our proposed protocol has O(log n) time complexity and high-performance.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.2
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• pp.239-244
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• 2011

Nano Imprint Lithography(NIL) is technique for copying a pattern from stamp with nano size pattern in order to replicated the materials. It is very important to demold in order to make NIL process effectively. Self Assembled Monolayers(SAM) coater is manufactured by means of decreasing surface energy with the stamp surface treatment to improve release characteristics. Manufactured device contains tilting and rotation option for increasing process life time by coating on the sidewall of the pattern in stamp. The stamp coated with optimized tilting angle $30^{\circ}$ and rotation speed of 10rpm has more imprinting cycles than the stamping coated without tilting and rotation. Effective SAM coating on the sidewall of the pattern in stamp will improve by 50% of process life time.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.7
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• pp.173-180
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• 2016

Since smartphones possess a variety of user information, we can derive useful data related to the case from app data analysis in the digital forensic perspective. However, it requires an appropriate forensic measure as smartphone has the property of high mobility and high possibility of data loss, forgery, and modulation. Especially the forged/modulated time-stamp impairs the credibility of digital proof and results in the perplexity during the timeline analysis. This paper provides traces of usage which could investigate whether the time-stamp has been forged/modulated or not within the range of iOS based devices.

• Advances in aircraft and spacecraft science
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• v.3 no.1
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• pp.29-43
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• 2016

Composite materials are rapidly gaining popularity as an alternative to metals for structural and load bearing applications in the aerospace, automotive, alternate energy and consumer industries. With the advent of thermoplastic composites and advances in recycling technologies, fully recyclable composites are gaining ground over traditional thermoset composites. Stamp forming as an alternative processing technique for sheet products has proven to be effective in allowing the fast manufacturing rates required for mass production of components. This study investigates the feasibility of using the stamp forming technique for the processing of thermoplastic, recyclable composite materials. The material system used in this study is a self-reinforced polypropylene composite material (Curv$^{(R)}$). The investigation includes a detailed experimental study based on strain measurements using a non-contact optical measurement system in conjunction with stamping equipment to record and measure the formability of the thermoplastic composites in real time. A Design of Experiments (DOE) methodology was adopted to elucidate the effect of process parameters that included blank holder force, pre heat temperature and feed rate on stamp forming. DOE analyses indicate that feed rate had negligible influence on the strain evolution during stamp forming and blank holder force and preheat temperature had significant effect on strain evolution during forming.

• Korean Journal of Materials Research
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• v.15 no.9
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• pp.589-593
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• 2005

Nanoimprinting lithography (NIL) is known as a suitable technique for fabricating nano and micro structures of high definition. Hot embossing is one of NIL techniques and can imprint on thin films and bulk polymers. Key issues of hot embossing are time and expense needed to produce a stamp withstanding a high temperature and pressure. Fabrication of a metal stamp such as an electroplated nickel is cost intensive and time consuming. A ceramic stamp made by silicon is easy to break when the pressure is applied. In this paper, a plastic stamp using a high temperature epoxy was fabricated and tested. The plastic stamp was relatively inexpensive, rapid to produce and durable enough to withstanding multiple hot embossing cycles. The merits of low viscosity epoxy solutions were a fast degassing and a rapid filling the microstructures. The hot embossing process with plastic stamp was performed on PMMA substrates. The hot embossing was conducted at 12.6 bar, $120^{\circ}C$ and 10 minutes. An imprinted PMMA wafer was almost same value of the plastic stamp after 10 times embossing. Entire fabrication process from silicon master to plastic stamp was completed within 12 hours.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.5
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• pp.1117-1124
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• 2015

This paper explains a web session management system for mobile web environment with BYOD(Bring Your Own Device). This system operates by enhanced secure session token. This system consists of an unique identifier, time stamp, and encryption algorithm. The Unique identifier in this system classifies each mobile device for web security based on mobile environment with BYOD. And the Time stamp in this system that determine session effectiveness for web security. Also the Cipher algorithm in this system that protects session token information for web security. This paper analysis a security of session management system running on mobile web environment using the simulation techniques. The proposed method is more suitable than the other methods under enviroment mobile web environment with BYOD.