5 results on '"Cheng, Pu‐Jen"'
Search Results
2. End-to-End Video Question-Answer Generation With Generator-Pretester Network.
- Author
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Su, Hung-Ting, Chang, Chen-Hsi, Shen, Po-Wei, Wang, Yu-Siang, Chang, Ya-Liang, Chang, Yu-Cheng, Cheng, Pu-Jen, and Hsu, Winston H.
- Subjects
VIDEOS ,BASE pairs ,SUPERVISED learning - Abstract
We study a novel task, Video Question-Answer Generation (VQAG), for challenging Video Question Answering (Video QA) task in multimedia. Due to expensive data annotation costs, many widely used, large-scale Video QA datasets such as Video-QA, MSVD-QA and MSRVTT-QA are automatically annotated using Caption Question Generation (CapQG) which inputs captions instead of the video itself. As captions neither fully represent a video, nor are they always practically available, it is crucial to generate question-answer pairs based on a video via Video Question-Answer Generation (VQAG). Existing video-to-text (V2T) approaches, despite taking a video as the input, only generate a question alone. In this work, we propose a novel model Generator-Pretester Network that focuses on two components: (1) The Joint Question-Answer Generator (JQAG) which generates a question with its corresponding answer to allow Video Question “Answering” training. (2) The Pretester (PT) verifies a generated question by trying to answer it and checks the pretested answer with both the model’s proposed answer and the ground truth answer. We evaluate our system with the only two available large-scale human-annotated Video QA datasets and achieves state-of-the-art question generation performances. Furthermore, using our generated QA pairs only on the Video QA task, we can surpass some supervised baselines. As a pre-training strategy, we outperform both CapQG and transfer learning approaches when employing semi-supervised (20%) or fully supervised learning with annotated data. These experimental results suggest the novel perspectives for Video QA training. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
3. Cocluster hypothesis and ranking consistency for relevance ranking in web search.
- Author
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Jiang, Jian‐De, Jiang, Jyun‐Yu, and Cheng, Pu‐Jen
- Subjects
HYPOTHESIS ,DATABASE management ,INFORMATION retrieval ,INFORMATION storage & retrieval systems ,MEDICAL databases ,EVALUATION of organizational effectiveness ,PROGRAMMING languages ,STUDY skills ,SUPERVISION of employees ,WORLD Wide Web ,INTERNET searching ,SEARCH engines ,FINANCIAL management ,SOFTWARE architecture ,ACCESS to information ,KNOWLEDGE base ,CITATION analysis - Abstract
Conventional approaches to relevance ranking typically optimize ranking models by each query separately. The traditional cluster hypothesis also does not consider the dependency between related queries. The goal of this paper is to leverage similar search intents to perform ranking consistency so that the search performance can be improved accordingly. Different from the previous supervised approach, which learns relevance by click‐through data, we propose a novel cocluster hypothesis to bridge the gap between relevance ranking and ranking consistency. A nearest‐neighbors test is also designed to measure the extent to which the cocluster hypothesis holds. Based on the hypothesis, we further propose a two‐stage unsupervised approach, in which two ranking heuristics and a cost function are developed to optimize the combination of consistency and uniqueness (or inconsistency). Extensive experiments have been conducted on a real and large‐scale search engine log. The experimental results not only verify the applicability of the proposed cocluster hypothesis but also show that our approach is effective in boosting the retrieval performance of the commercial search engine and reaches a comparable performance to the supervised approach. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
4. An Efficient Multiple Session Key Establishment Scheme for VANET Group Integration.
- Author
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Lee, Cheng-Chi, Lai, Yan-Ming, and Cheng, Pu-Jen
- Subjects
VEHICULAR ad hoc networks ,WIRELESS sensor networks ,KEY agreement protocols (Computer network protocols) ,CHINESE remainder theorem ,COMPUTER network security - Abstract
VANET (vehicular ad hoc network) is used to create communication networks for vehicles or other roadside devices so that they can quickly share and receive messages. However, VANET belongs to a family of wireless networks, which means that its functions are unsafe. To provide safe communication channels, key-agreements technology can be introduced to VANET communication. Traditional key-agreement schemes, however, are inefficient and consume too many resources, especially when handling large or combined groups of users. To improve efficiency, the Chinese remainder theorem is used to build a batch key-agreement protocol. The improved key for VANET environments is a safer and quicker way to establish communication channels. [ABSTRACT FROM PUBLISHER]
- Published
- 2016
- Full Text
- View/download PDF
5. A New Ticket-Based Authentication Mechanism for Fast Handover in Mesh Network.
- Author
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Lai, Yan-Ming, Cheng, Pu-Jen, Lee, Cheng-Chi, and Ku, Chia-Yi
- Subjects
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WIRELESS mesh networks , *ROAMING (Telecommunication) , *INTERNET access , *COMPUTER network security , *TAMPER-proof packaging , *SCALABILITY - Abstract
Due to the ever-growing popularity mobile devices of various kinds have received worldwide, the demands on large-scale wireless network infrastructure development and enhancement have been rapidly swelling in recent years. A mobile device holder can get online at a wireless network access point, which covers a limited area. When the client leaves the access point, there will be a temporary disconnection until he/she enters the coverage of another access point. Even when the coverages of two neighboring access points overlap, there is still work to do to make the wireless connection smoothly continue. The action of one wireless network access point passing a client to another access point is referred to as the handover. During handover, for security concerns, the client and the new access point should perform mutual authentication before any Internet access service is practically gained/provided. If the handover protocol is inefficient, in some cases discontinued Internet service will happen. In 2013, Li et al. proposed a fast handover authentication mechanism for wireless mesh network (WMN) based on tickets. Unfortunately, Li et al.’s work came with some weaknesses. For one thing, some sensitive information such as the time and date of expiration is sent in plaintext, which increases security risks. For another, Li et al.’s protocol includes the use of high-quality tamper-proof devices (TPDs), and this unreasonably high equipment requirement limits its applicability. In this paper, we shall propose a new efficient handover authentication mechanism. The new mechanism offers a higher level of security on a more scalable ground with the client’s privacy better preserved. The results of our performance analysis suggest that our new mechanism is superior to some similar mechanisms in terms of authentication delay. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
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