• The Journal of Bigdata
• /
• v.7 no.2
• /
• pp.129-137
• /
• 2022

With the development of the 4th industry, the logistics industry is evolving into a smart logistics system. However, ship work that transports vehicles is progressing slowly due to various problems. In this paper, we propose an stowage automation algorithm that can be used for cargo loading of vehicle carriers that shortens loading and unloading work time. The stowage automation algorithm returns the shortest distance by searching for a loading space and a movable path in the ship in consideration of the structure of the ship. The algorithm identifies walls, ramps and vehicles that have already been shipped, and can work even with randomly placed. In particular, it is expected to contribute to developing a smart logistics system for vehicle carriers by referring to the ship's master plan to search for vehicle loading and unloading space in each port and predict the shortest movable path.

• Journal of the Korea Society of Computer and Information
• /
• v.18 no.2
• /
• pp.69-76
• /
• 2013

Reader-to-reader interference in RFID system is occurred due to the use of limited number of frequencies, and this is the main cause of read rate reduction in the passive RFID tags. Therefore, in order to maximize the read rate under the circumstances of limited frequency resources, it is necessary to minimize the frequency interference among RFID readers. This paper presents a hybrid FDM/TDM constraint satisfaction problem models for frequency interference minimization problems of the RFID readers, and assigns optimal channels to each readers using conventional backtracking search algorithms. A depth first search based on backtracking are accomplished to find solutions of constraint satisfaction problems. At this moment, a variable ordering algorithm is very important to find a solution quickly. Variable ordering algorithms applied in the experiment are known as efficient in the graph coloring. To justify the performance of the proposed constraint satisfaction problem model, optimal channels for each readers in the passive UHF RFID system are allocated by using computer simulation satisfying various interference constraints.

• The KIPS Transactions:PartB
• /
• v.10B no.5
• /
• pp.575-578
• /
• 2003

SPIHT algorithm is a wavelet based fast and effective technique for image compression. It uses a list structure to store status information which is generated during set-partitioning of zero-tree. Usually, this requires lots of additional memory depending on how high the bit-rate is. Therefore, in this paper, we propose a new technique called MZP-DFS, which needs no additional memory when running SPIHT algorithm. It traverses a spatial-tree according to DFS and eliminates additional memory as it uses test-functions for encoding and LSB bits of coefficients for decoding respectively. This method yields nearly the same performance as SPIHT. This may be desirable in hardware implementation because no additional memory is required. Moreover. it exploits parallelism to process each spatial-tree that it can be applied well in real-time image compression.

• Proceedings of the Korean Information Science Society Conference
• /
• 2005.11b
• /
• pp.16-18
• /
• 2005

웹은 사용자가 원하는 정보를 쉽고 정확하게 검색할 수 있도록 웹 문서를 자료구조화하여 보다 신뢰성 있는 패턴을 추출하고 사용자의 특성과 행동 패턴을 적용하여 개인화 하여야한다. 본 논문에서는 개인화하기 위한 전처리 과정으로서 웹 문서를 구조화 하는 방법을 제안한다. 제안 방법은 기본적으로 웹 문서 태그의 하이퍼링크를 깊이 우선 탐색 알고리즘을 사용하여 방향그래프를 만드는 것이다. 이때 웹 문서 태그 탐색 시 플래시, 스크립트 등의 찾기 힘든 하이퍼링크를 찾는 문제와 '뒤로' 버튼 사용 시 웹 접근로그에 기록되지 않는 문제점을 보완한다. 이를 위해 클릭 스트림을 스택에 저장하여 이미 만들어진 방향그래프와 비교하여 새롭게 찾은 정점과 간선을 추가함으로써 보다 신뢰성높은 방향그래프를 만든다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2006.11a
• /
• pp.393-396
• /
• 2006

웹의 급속한 성장으로 정보의 양이 많아졌지만 디자인의 비중이 커지면서 웹 문서에 대한 구조를 추출하는데 어려움이 있다. 웹은 사용자가 원하는 정보를 쉽고 정확하게 검색할 수 있도록 웹 문서의 내용을 구조화하여 지속적으로 개선하면서 사용자의 특성과 행동 패턴에 따라 개인화 하여야한다. 이러한 문제를 해결하기 위해서는 웹 문서들 간의 정확한 구조를 추출하는 것이 선행되어야 한다. 본 논문에서는 보다 웹 사이트의 정확한 구조를 추출하기 위한 방법을 제안한다. 제안 방법은 기본적으로 웹문서 태그의 하이퍼링크와 플래시 파일을 2진 형태의 문서로 불러 하이퍼링크를 추출하고 이를 깊이 우선 탐색 알고리즘을 사용하여 방향그래프로 만든다. 하지만 이러한 웹 문서 태그 탐색 시 애플릿이나 스크립트 등에 숨어 있는 하이퍼링크를 찾는 문제와 '뒤로' 버튼 사용 시 웹 접근로그에 기록되지 않는 문제점이 보완되어야 한다. 이를 위해 클릭 스트림을 스택에 저장하여 이미 만들어진 방향그래프와 비교하여 새롭게 찾은 정점과 간선을 추가 삭제함으로써 보다 신뢰성 높은 방향 그래프를 만든다.

• The KIPS Transactions:PartD
• /
• v.12D no.6 s.102
• /
• pp.807-816
• /
• 2005

Sequential pattern mining finds all of the frequent sequences satisfying a minimum support threshold in a large database. However, when mining long frequent sequences, or when using very low support thresholds, the performance of currently reported algorithms often degrades dramatically. In this paper, we propose a novel sequential pattern algorithm using only closed frequent sequences which are small subset of very large frequent sequences. Our algorithm generates the candidate sequences by depth-first search strategy in order to effectively prune. using bitmap representation of underlying databases, we can effectively calculate supports in terms of bit operations and prune sequences in much less time. Performance study shows that our algorithm outperforms the previous algorithms.

• The KIPS Transactions:PartC
• /
• v.10C no.6
• /
• pp.683-694
• /
• 2003

We present X-tree Diff, a change detection algorithm for tree-structured data. Our work is motivated by need to monitor massive volume of web documents and detect suspicious changes, called defacement attack on web sites. From this context, our algorithm should be very efficient in speed and use of memory space. X-tree Diff uses a special ordered labeled tree, X-tree, to represent XML/HTML documents. X-tree nodes have a special field, tMD, which stores a 128-bit hash value representing the structure and data of subtrees, so match identical subtrees form the old and new versions. During this process, X-tree Diff uses the Rule of Delaying Ambiguous Matchings, implying that it perform exact matching where a node in the old version has one-to one corrspondence with the corresponding node in the new, by delaying all the others. It drastically reduces the possibility of wrong matchings. X-tree Diff propagates such exact matchings upwards in Step 2, and obtain more matchings downwsards from roots in Step 3. In step 4, nodes to ve inserted or deleted are decided, We aldo show thst X-tree Diff runs on O(n), woere n is the number of noses in X-trees, in worst case as well as in average case, This result is even better than that of BULD Diff algorithm, which is O(n log(n)) in worst case, We experimented X-tree Diff on reat data, which are about 11,000 home pages from about 20 wev sites, instead of synthetic documets manipulated for experimented for ex[erimentation. Currently, X-treeDiff algorithm is being used in a commeercial hacking detection system, called the WIDS(Web-Document Intrusion Detection System), which is to find changes occured in registered websites, and report suspicious changes to users.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.24 no.7B
• /
• pp.1239-1251
• /
• 1999

In this paper a scalable QoS-based hierarchical inter-domain routing scheme for distributed multimedia applications in a high speed wide area network. The problem of QoS-based routing is formulated as a multicriteria shortest path problem, known as NP-complete[21,30]. Our routing scheme consists of two phases. In Phase 1, two graph construction algorithms are performed to model the network under consideration as a graph. The graph contains a part of the network topology which is completely neglected or partially considered by existing routing schemes, thus maintaining more accurate topology information. In Phase 2, a heuristic call-by-call algorithm is performed for selecting a feasible path efficiently in depth first search-like manner on the graph and tailoring to each application's QoS requirements, beginning at a vertex that represents the source node. In this paper, a simple rule is also produced, by which the visiting order of outgoing edges at each vertex on the graph is determined. The rule is based on each edge's the minimum normalized slackness to the QoS requested. The proposed routing scheme extends the PNNI-type hierarchical routing framework. Note that our routing scheme is one of a few QoS-based hierarchical routing schemes that address explicitly the issue of selecting a path with multiple metrics.