Search Word(s) in Title, Keywords, Authors, and Abstract: Min Choi

A Simple and Effective Combination of User-Based and Item-Based Recommendation Methods
Se-Chang Oh and Min Choi
Page: 127~136, Vol. 15, No.1, 2019
10.3745/JIPS.01.0036
Keywords: Collaborative Filtering, Electronic Commerce, Recommender System, Sparsity
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User-based and item-based approaches have been developed as the solutions of the movie recommendation problem. However, the user-based approach is faced with the problem of sparsity, and the item-based approach is faced with the problem of not reflecting users’ preferences. In order to solve these problems, there is a research on the combination of the two methods using the concept of similarity. In reality, it is not free from the problem of sparsity, since it has a lot of parameters to be calculated. In this study, we propose a combining method that simplifies the combination equation of prior study. This method is relatively free from the problem of sparsity, since it has less parameters to be calculated. Thus, it can get more accurate results by reflecting the users rating to calculate the parameters. It is very fast to predict new movie ratings as well. In experiments for the proposed method, the initial error is large, but the performance gets quickly stabilized after. In addition, it showed about 6% lower average error rate than the existing method using similarity.


Implementation of Multipurpose PCI Express Adapter Cards with On-Board Optical Module
Kyungmo Koo, Junglok Yu, Sangwan Kim, Min Choi and Kwangho Cha
Page: 270~279, Vol. 14, No.1, 2018
10.3745/JIPS.01.0022
Keywords: Device Network, Interconnection Network, On-Board Optical Module, PCI Express Bus
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PCI Express (PCIe) bus, which was only used as an internal I/O bus of a computer system, has expanded its function to outside of a system, with progress of PCIe switching processor. In particular, advanced features of PCIe switching processor enable PCIe bus to serve as an interconnection network as well as connecting external devices. As PCIe switching processors more advanced, it is required to consider the different adapter card architecture. This study developed multipurpose adapter cards by applying an on-board optical module, a latest optical communications element, in order to improve transfer distance and utilization. The performance evaluation confirmed that the new adapter cards with long cable can provide the same bandwidth as that of the existing adapter cards with short copper cable.


Feasibility and Performance Analysis of RDMA Transfer through PCI Express
Min Choi and Jong Hyuk Park
Page: 95~103, Vol. 13, No.1, 2017
10.3745/JIPS.01.0013
Keywords: Interconnection Network, Non-transparent Bridge, PCI Express, RDMA
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The PCI Express is a widely used system bus technology that connects the processor and the peripheral I/O devices. The PCI Express is nowadays regarded as a de facto standard in system area interconnection network. It has good characteristics in terms of high-speed, low power. In addition, PCI Express is becoming popular interconnection network technology as like Gigabit Ethernet, InfiniBand, and Myrinet which are extensively used in high-performance computing. In this paper, we designed and implemented a evaluation platform for interconnect network using PCI Express between two computing nodes. We make use of the non-transparent bridge (NTB) technology of PCI Express in order to isolate between the two subsystems. We constructed a testbed system and evaluated the performance on the testbed.