• Title/Summary/Keyword: Lock-In

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Secure Oblivious Transfer Protocol-based Digital Fingerprinting Against Conspiracy Attack (공모 공격에 안전한 불확정 전송 프로토콜 기반의 디지털 핑거프린팅 기법)

  • 최재귀;박지환;김태석
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.14 no.3
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    • pp.145-153
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    • 2004
  • Digital fingerprinting schemes are cryptographic methods that a seller can identify a traitor who illegally redistributed digital contents by embedding it into buyer's information. Recently, Josep Domingo-Ferrer suggested an anonymous digital fingerprinting scheme based on committed oblivious transfer protocol. It is significant in the sense that it is completely specified from a computation point of view and is thus readily implementable. But this scheme has the serious problem that it cannot provide the security of buyers. In this paper, we first show how to break the existing committed oblivious transfer-based fingerprinting schemes and then suggest secure fingerprinting scheme by introducing oblivious transfer protocol with two-lock cryptosystem based on discrete logarithm. All computations are performed efficiently and the security degree is strengthened in our proposal.

Improving Lock Performance of Home-base Lazy Release Consistency (Home-based Lazy Release Consistency의 락 성능향상)

  • Yun, Hui-Cheol;Lee, Sang-Gwon;Lee, Jun-Won;Maeng, Seung-Ryeol
    • Journal of KIISE:Computer Systems and Theory
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    • v.28 no.10
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    • pp.513-519
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    • 2001
  • Home-based Lazy Release Consistency (HLRC) shows poor performance on lock based applications because of two reasons:(1) a whole page is fetched on a page fault while actual modification is much smaller , and(2) the home is at the fixed location while access pattern is migratory, In this paper we present an efficient lock protocol for HLRC. In this protocol, the pages that are expected to be used by acquirer selectively updated using diffs. The diff accumulation problem is minimized by limiting the size of diffs to be sent for each page. Our protocol reduces the number or page faults inside critical sections because pages can be updated by applying locally stored diffs . This reduction yields the reduction of average lock waiting time and the reduction of message amount. The experiment with five applications shows that our protocol archives 2%~40% speedup against base HLRC for four applications.

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TTL : An automatic door lock system utilizing time and applications (TTL : 시간과 어플리케이션을 활용한 자동 도어락 시스템)

  • Jung, Jin-young;Moon, Sangook
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2015.05a
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    • pp.900-902
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    • 2015
  • Doors are to be the most basics of our lives from opening, closing and even keeping our property. Hence, doors have been innovated to blend in and make our daily lives more convenient. However, we find it difficult to open and close the doors manually of offices or tour zones, where they open and close at a precise time everyday. To solve this, we added a dimension of time to previous Door Locks. By this, every door with this specific door lock will open and close at a certain time we want them to open or close. Also, through the application you can control the time or use it to open and close the doors remotely. In order to do this, we systemed the door lock time system based on Java Programing language to make it easy to communicate and open or close the doors through smart phone applications, with the C programming language for the ATmega128 which will open and close the doors.

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Vibration Characteristics and Topology Optimization of a Double Damper Lock-Up Clutch in a Torque Converter System (토크컨버터 장착 이중댐퍼 체결클러치의 진동특성해석 및 위상최적화)

  • Kim, Kwang-Joong;Kim, Cheol
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.8
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    • pp.1129-1136
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    • 2010
  • Damper springs in a drive-line absorb the impulsive torque generated when a lock-up clutch is connected directly, instead of via a fluid coupling. Design optimization and finite element analysis were performed to improve the shock- and vibration-absorption capacity of the lock-up clutch. For this purpose, a multi-body dynamics model was developed by including the main parts of a vehicle, such as an engine with a clutch, a transmission, drive shafts and wheels, and a whole mass of a vehicle. The spring constants were selected so that resonance of a system could be avoided. Damper springs were optimized on the basis of the spring constants, impulsive torques, compressed angles, spring counts, fatigue constraints, etc. Topology optimization was performed for three plates with the damper springs. The compliance was set up as an objective function, and volume fraction was fixed below 0.3. A new shape for the plates was proposed on the basis of the topology result.

Implementation of a Single Human Detection Algorithm for Video Digital Door Lock (영상디지털도어록용 단일 사람 검출 알고리즘 구현)

  • Shin, Seung-Hwan;Lee, Sang-Rak;Choi, Han-Go
    • The KIPS Transactions:PartB
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    • v.19B no.2
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    • pp.127-134
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    • 2012
  • Video digital door lock(VDDL) system detects people who access to the door and acquires the human image. Design considerations is that current consumption must be minimized by applying fast human detection algorithm because of battery-based operation. Since the digital door lock takes an image through a fixed camera, detection of a person based on background image leads to high degree of reliability. This paper deals with a single human detection algorithm suitable for VDDL with fulfilling these requirements such that it detects a moving object in an image, then identifies whether the object is a person or not using image processing. The proposed image processing algorithm consists of two steps: Firstly, it detects the human image region using both background image and skin color information. Secondly, it identifies the person using polar histogram based on proportional information of human body. Proposed algorithm is implemented in VDDL and is verified the performance through experiments.

Effect of Slip-Controlled Torque Converter Damper Clutch in 5-Speed Automatic Transmission on Slip Rate and Fuel Economy (5속 A/T용 자동변속기 토크컨버터 댐퍼클러치 슬립제어가 슬림율과 연비에 미치는 영향)

  • Lee, Gee-Soo;Kim, Deok-Jung;Kim, Hyun-Chul;Na, Byung-Chul;Heo, Hyung-Seok;Lee, Ho-Gil;Jang, Jae-Duk
    • Transactions of the Korean Society of Automotive Engineers
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    • v.17 no.3
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    • pp.74-80
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    • 2009
  • The objective of this paper was to investigate the slip rate and the slip frequency number of damper clutch of torque converter in 2.4L passenger vehicle with 5-speed A/T and analyze the effect of slip control and control strategy on driving characteristics and the fuel economy. The newly developed torque converter with the more durable wet friction material and the slip-controlled damper clutch system, the DCC system, was installed, which was easily compatible and amendable of the lock-up clutch of the base system. The vehicle has been tested on the fuel economy modes such as FTP-75, HWFET and NEDC (ECE15+EUDC) driving cycle at chassis dynamometer. The DCC mode (II), of which the control strategy had both the lock-up and the slip-controlled clutch, and the DCC mode (I) with full slip-controlled clutch were compared with the base system with only the lock-up clutch. As the research result, comparison to base system, the fuel consumption of the vehicle with the DCC control (II) was effectively improved by 6.6% and 7.7% on FTP-75 and NEDC mode.

A Study on Competitiveness-reinforcing Factors in Designing Digital Door Lock Products and in Penetrating the Market -With Focus on an Analysis of Consumers' Preference by Product- (디지털 도어락 시장 진입을 위한 제품디자인의 경쟁력 장화요소 연구 - 제품별 소비자 선호도 분석을 중심으로 -)

  • Yoo, Boo-Mee
    • Archives of design research
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    • v.18 no.1 s.59
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    • pp.135-144
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    • 2005
  • Consumers' awareness of product value, and their product preferences, are becoming increasingly influential in product development, particularly in corporations' efforts in manufacturing products with a competitive edge. Corporations conduct surveys on consumers' product satisfaction and preferences and conduct in-depth studies on consumer needs. They then manufacture products in accordance with the results of these surveys and studies. With the necessity and demand for digital door lock products recently growing, this research sought to explore product competitiveness reinforcement factors that could facilitate market penetration, and to formulate corresponding design strategies. In-depth consumer interviews were also conducted to identify consumer lifestyles and needs. Furthermore, consumer preference images, purchase and use-related patterns, and the status of door lock markets were studied. In the past, to design and manufacture consumer-oriented products, corporations primarily resorted to the improvement of the products' technological features. At present, the users' product preferences and the ways that they use these products are the factors that determine product design. Consumers today tend to adjust their lifestyles according to available products, and prefer products that have greater value in terms of lifestyle and culture. Strategic points for reinforcing competitiveness were presented in this study: first, offering different values that will enhance consumer satisfaction, second, positively developing bio-recognizable methods that will boost consumer preference, third, meeting the consumers' expectations that door lock products should not be mere 'entrance and exit control' systems, but network security systems and fourth, adopting convenient authentication methods backed by advanced technologies.

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Network Effects and Dynamic Capabilities (네트워크 효과와 동태적 경쟁역량)

  • Lee, Jong-Seok
    • Korean Business Review
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    • v.19 no.2
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    • pp.183-206
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    • 2006
  • Recently, the notion of "increasing returns" has been popular not only in academia but also in industries. This notion has been drawn from prior research on network effects, which showed that the market evolution would lock in to a dominant technology. However, the long history of technological change has rarely shown the possibility of lock-in to an inferior technology. How could the market with network effects make transition between incompatible technologies regimes by escaping the lock-in? This paper analyzes the effectiveness of R&D and technological choice to investigate the sources of the dynamic capabilities in the presence of network effects and uncertain technological progress. Why does the market sometimes work against a radical technology, and why, at other times, does the market operate in favor of it? This study is to address this question by modeling the situation of two competing technologies in the presence of network effects. The numerical analysis indicates that the evolution strategy of compatibility is more likely to increase the chance of firm growth when a majority of customers are not power users or when demand for an old technology has been escalated. But when there are a substantial number of power users or when a new technology emerges before such an escalation of demand, the revolution strategy of compelling performance is more likely to be effective. The result suggests a potential mechanism for overcoming the lock-in problem. When the market exhibits some inertia to an obsolete technology, which is reinforced by the increasing customer value with respect to backward compatibility, the survival of a new technology depends on power users. When many power users are cultivated by firms' technological efforts regarding the new technology, the market is less likely to lock into an obsolete technology. Indeed, in the workstation market, where power users characterize much of the demand, innovators like Sun successfully switched to the RISC architecture.

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Current Limiting and Voltage Sag Compensation Characteristics of Flux-Lock Type SFCL Using a Transformer Winding (변압기 권선을 이용한 자속구속형 초전도 전류제한기의 전류제한 및 전압강하 보상 특성)

  • Ko, Seok-Cheol
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.25 no.12
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    • pp.1000-1003
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    • 2012
  • The superconducting fault current limiter (SFCL) can quickly limit the fault current shortly after the short circuit occurs and recover the superconducting state after the fault removes and plays a role in compensating the voltage sag of the sound feeder adjacent to the fault feeder as well as the fault current limiting operation of the fault feeder. Especially, the flux-lock type SFCL with an isolated transformer, which consists of two parallel connected coils on an iron core and the isolated transformer connected in series with one of two coils, has different voltage sag compensating and current limiting characteristics due to the winding direction and the inductance ratio of two coils. The current limiting and the voltage sag compensating characteristics of a SFCL using a transformer winding were analyzed. Through the analysis on the short-circuit tests results considering the winding direction of two coils, the SFCL designed with the additive polarity winding has shown the higher limited fault current than the SFCL designed with the subtractive polarity winding. It could be confirmed that the higher fault current limitation of the SFCL could be contributed to the higher load voltage sag compensation.

Evaluation on the Structural Performance of Hybrid Damper Using High-damping Rubber and Steel (고감쇠고무와 강재를 이용한 복합제진댐퍼의 구조성능평가)

  • Kim, Ji-Young;Jung, In-Yong;Kim, Hyung-Geun;Kim, Do-Hyun
    • Journal of Korean Association for Spatial Structures
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    • v.16 no.3
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    • pp.99-106
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    • 2016
  • The proposed hybrid damper installs at a coupling beam and consists of a high-damping rubber (HDR) and steel pin. The proposed hybrid damper adopted a pin-lock system acts as a viscoelastic damper under wind load (small displacement) while it behaves as a hysteretic damper under earthquake load (large displacement). In this paper, the pin-lock mechanism and structural performance of the proposed hybrid damper is evaluated through experiment. Experiments were carried out with the variables which displacement, loading frequency and steel pin quantities were used. Test results showed that the pin-lock mechanism and the performance of the hybrid damper under a large displacement were verified. Also equivalent damping ratios of HDR were increasing at a small displacement as displacement amplitudes were increasing. However HDR did not depend on frequency.