• Journal of KIISE:Software and Applications
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• v.26 no.1
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• pp.1-15
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• 1999

대화식 UNDO는 수행된 연산을 철회시키거나 재실행시킴으로서 사용자의 오류를 쉽게 교정할 수 있도록 허용하기 위한 일종의 회복기능이다. 소프트웨어 개발, 하이퍼미디어 CAD 등과 같은 새로운 데이터베이스응용 분야에서는 편리한 저작 및 편집 과정으르 위하여 대화식 UNDO 기능의 지원이 필수적이다. 상용 DBMS들이 제공하는 세이브포인트를 이용한 부분 철회는 수행된 연산의 철회만을 허용하는 것으로 대화식 UNDO의 제한적 기능이다. 기존의 응용 시스템들은 데이터 관리를 위해서는 DBMS를 사용하면서도 이러한 대화식 UNDO 기능은 응용시스템에서 직접 제공하고 있다. 대화식 UNDO 기능의 구현은 매우 복잡하기 때문에 응용 프로그래머에게 상당한 개발 오버헤드를 요구한다. 본 연구의 목적은다양한 응용 시스템개발을 위하여 공통적으로 필요한 고급 기능을 응용 프로그래머가 쉽게 이용할 수 있도록 대화식 UNDO 기능을 DBMS에서 직접 지원하는 새로운 회복 기법을 제안하는 것이다. 제안된 기법에서는 트랜잭션 철회시 대화식 UNDO에 의해 UNDO된 연산들을 스킵함으로써 빠른 철회를 보장하고 여러 연산을 한번에 철회할 수 있는 벌크 UNDO 연산 (bulk undo)을 제공한다. 벌크들도 다시 재실행될수 있다는 점에서 부분 철회와 구별된다. 특히,일반 DBMS에서 회복을 위하여 관리해야 하는 정보를 최대한 활용함으로써 새로운 기능의 추가에도 불구하고 제안된 기법의 성능은 이러한 기능을 제공하지 않는 기존의 회복 기법과 비교할만한 좋은 성능을 보인다.

• Journal of Korea Multimedia Society
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• v.19 no.8
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• pp.1544-1552
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• 2016

If the undo/redo function is not reflected in the initial design of an application, it makes it difficult to implement the undo/redo function additionally, in this paper, we examined some examples to design the sodoku game and analyzed problems of the design to implement the undo/redo functions. For an efficient design of the undo/redo functions without using swing.undo package, we propose a class design using the Command, Memento, and Observer pattern these are used as organic. The proposed method is more efficient for distributed work than other method. We implemented a sudoku game using proposed design. In the undo/redo function testing, we could see that it works well.

• Journal of Computational Design and Engineering
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• v.1 no.2
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• pp.103-115
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• 2014

The engineering design process is a creative process, and the designers must repeatedly apply Undo/Redo operations to modify CAD models to explore new solutions. Undo/Redo has become one of most important functions in interactive graphics and CAD systems. Undo/Redo in a collaborative CAD system is also very helpful for collaborative awareness among a group of cooperative designers to eliminate misunderstanding and to recover from design error. However, Undo/Redo in a collaborative CAD system is much more complicated. This is because a single erroneous operation is propagated to other remote sites, and operations are interleaved at different sites. This paper presents a multi-user selective Undo/Redo approach in full distributed collaborative CAD systems. We use site ID and State Vectors to locate the Undo/Redo target at each site. By analyzing the composition of the complex CAD model, a tree-like structure called Feature Combination Hierarchy is presented to describe the decomposition of a CAD model. Based on this structure, the dependency relationship among features is clarified. B-Rep re-evaluation is simplified with the assistance of the Feature Combination Hierarchy. It can be proven that the proposed Undo/Redo approach satisfies the intention preservation and consistency maintenance correctness criteria for collaborative systems.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04b
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• pp.125-127
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• 2000

ISO TC211에서는 응용 스키마에서 공간 객체의 공간 관련성을 피처간의 위상 관련성으로 기술되어야 함을 규칙으로 정하고 있다. 따라서 공간 데이터가 변경되거나 변경 중 복귀될 때도 객체간의 공간 관련성은 유지되어야 한다. 공간 관련성을 유지하기 위해서 기존의 회복 기법을 적용하면 수정의 결과가 다른 트랜잭션에 영향을 미치는 특징 때문에 많은 연쇄 복귀가 발생한다. 따라서 공간 데이터 변경 트랜잭션의 회복에 적용하기 어렵다. 또한 협동 수정 트랜잭션의 회복 기법은 한 트랜잭션의 UNDO에 의해 모든 협동 트랜잭션이 연쇄 복귀되는 문제가 있다. 본 논문에서는 클라이언트-서버 GIS에서 공간 관련성을 이용하여 관련된 트랜잭션을 선택적으로 복귀하는 회복 기법을 제시한다. 그리고 서브-트랜잭션 단위의 UNDO를 위해 로그 레코드 구조를 제시하며 UNDO 결과를 효율적으로 전파하기 위한 기법을 제시한다.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.746-751
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• 2006

The geumjunggu of the onchunchun which is the upper stream have been maintained as a too much picture to become a concrete lining about existing low flow channel and the reservoir water protecting banks for the reason of the flow of an upper stream steep slope and back of the shortage of the channel area in a suitableness interval. This research made a rating-curve to decide since to ensure against risks to the flood control through the undo of the rivers. And we found the speed of current of a nature undo interval and existing concrete interval and water level change out. A result from this natural disposition we must apply as a data for the research about the plan to be established in the rivers maintenance basis plan of onchunchun.

• Journal of KIISE:Databases
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• v.30 no.1
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• pp.64-79
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• 2003

In client-server computing environments, update transactions of spatial data have the following characteristics. First, a transaction to update maps needs interactive work, and therefore it nay take a long time to finish. Second, a long transaction should be allowed to read the dirty data to enhance parallelism of executing concurrent transactions. when %he transaction is rolled back, it should guarantee the cascading rollback of all of the dependent transactions. Finally, two spatial objects may have a weak dependency constraint, called the spatial relationship, based on geometric topology. The existing recovery approaches cannot be directly applied to this environment, due to the high rollback cost and the overhead of cascading rollbacks. Furthermore, the previous approaches cannot guarantee the data integrity because the spatial relationship, which is a new consistency constraint of spatial data, is not considered. This paper presents new recovery schemes for update transactions of spatial data. To guarantee the data integrity, this paper defines recovery dependency as a rendition of cascading rollbacks. The partial-rollback is alto suggested to solve the problem of high rollback cost. The recovery schemes proposed in this paper can remove the unnecessary cascading rollbacks by using undo-delta, partial -redo and partial-undo. Finally, the schemes are performed to ensure the correctness.

• Journal of Korea Game Society
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• v.11 no.4
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• pp.15-26
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• 2011

Game level design is a collaborative work to create a virtual world for a computer game including maps, agents, monsters, objects, players and events based on predefined its game scenario. It is a promising collaborative design application. The game level design generally requires much time and cost, as the size of its target game space becomes huge. However, traditional game level design tools do not provide concurrency control mechanisms among multiple participating game designers. They do not provide consistency of undo and redo mechanisms for erroneous collaborative tasks during iterative modifications and updates of collaborative tasks among multiple designers. In this paper, we propose a concurrency control and a collaborative editing mechanism to enhance productivity of the collaborative game level design. The proposed system provides hierarchical structures of shared objects and a concurrency control mechanism for each object. The proposed system also provides a consistent undo and redo mechanism to enhance modifications and updates on intermediate results of the level design procedures.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04b
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• pp.190-192
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• 2000

MMDBMS(Main Memory Database Management System)에서 사용되는 갱신기법중 퍼지 검사점을 지원하는 직접갱신 기법은 많은 양의 로그를 필요로 하며 회복 과정이 복잡하다는 단점이 있다. 본 논문에서는 퍼지 검사점을 지원하면서 저장해야 할 로그의 양을 줄이고 회복 과정이 단순한 회복 기법을 제안한다. 제안하는 회복 기법은 로그의 양을 줄이고 위해 철회된 트랜잭션의 로그를 비휘발성 메모리에 저장하지 않는 시스템 구조와 많은 양의 메모리를 사용하지 않는 POLUG(Page Oritented Logical Undo loG)를 사용하여 퍼지 검사점을 지원할 수 있는 장점을 가진다.

• Journal of the Institute of Convergence Signal Processing
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• v.18 no.2
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• pp.31-36
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• 2017

This study aims to develop an BCI speller utilizing eye-closed and double-blinking EEG based on asynchronous mechanism. The proposed system comprised a signal processing module and a graphical user interface (virtual keyboard-VK) with 26 English characters plus a special symbol. A detected "eye-closed" event induces the "select" command, whereas a "double-blinking" (DB) event functions the "undo" command. A three-class support vector machine (SVM) classifier involving EEG signal analysis of three groups of events ("eye-open"-idle state, "eye-closed", and "double -blinking") is proposed. The results showed that the proposed BCI could achieve an overall accuracy of 92.6% and a spelling rate of 5 letters/min on average. Overall, this study showed an improvement of accuracy and the spelling rate resulting from in the feasibility and reliability of implementing a real-world BCI speller.

• Transactions on Control, Automation and Systems Engineering
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• v.4 no.1
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• pp.23-31
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• 2002

We proposed a concept of a desktop micro device factory for visually servoed teleoperated microassembly assisted by a virtual reality (VR) interface. It is composed of two micromanipulators equipped with micro tools operating under a light microscope. First a manipulator, control method for the micro object to follow a planned trajectory in pushing operation is proposed undo. vision based-position control. Then, we present the cooperation control strategy of the micro handling operation under vision-based force control integrating a sensor fusion framework approach. A guiding-system based on virtual micro-world exactly reconstructed from the CAD-CAM databases of the real environment being considered is presented for the imprecisely calibrated micro world. Finally, some experimental results of microassembly tasks performed on millimeter-sized components are provided.