• Title/Summary/Keyword: Cold Start Time

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Cross-Domain Recommendation based on K-Means Clustering and Transformer (K-means 클러스터링과 트랜스포머 기반의 교차 도메인 추천)

  • Tae-Hoon Kim;Young-Gon Kim;Jeong-Min Park
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.23 no.5
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    • pp.1-8
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    • 2023
  • Cross-domain recommendation is a method that shares related user information data and item data in different domains. It is mainly used in online shopping malls with many users or multimedia service contents, such as YouTube or Netflix. Through K-means clustering, embeddings are created by performing clustering based on user data and ratings. After learning the result through a transformer network, user satisfaction is predicted. Then, items suitable for the user are recommended using a transformer-based recommendation model. Through this study, it was shown through experiments that recommendations can predict cold-start problems at a lesser time cost and increase user satisfaction.

PM Reduction Characteristics of Partial Metal DPF with Screen Mesh Filter Structure (스크린 필터 구조 Partial Metal DPF의 PM 저감 특성)

  • Kim, Chunghui;Kim, Hyunchul;Lee, Geesoo;Choi, Jeonghwang;Chon, Munsoo;Shin, Suk Shin;Suh, Hyun Kyu
    • Transactions of the Korean Society of Automotive Engineers
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    • v.21 no.3
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    • pp.82-87
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    • 2013
  • In this work, the 1L grade integrated metal DOC/DPF filter that can install in engine manifold position was developed to investigate the effect of platinum-coating amount of filter on the improvement of filter activation temperature and reduction of particulate matter (PM). This filter was installed in 2.9L CI engine which meets the EURO-4 emission regulation. Tests for PM reduction efficiency of filter were conducted under ND-13 mode with full-load test condition. It was revealed that the time to reach the activation temperature of metal filter ($280^{\circ}C$) was shorter as the amount of platinum-coating increased. This short activation time can be helpful for the reduction of CO and HC emissions during cold start condition. At the same time, PM reduced as the coating amount increased. The reduction percentage of $DOC_{40}$, $DOC_{20}$, and $DOC_0$ were 96.7% (2.34 mg/kW'h), 95.1% (3.47 mg/kW'h), and 94.5% (3.69 mg/kW'h) compared to previous result (71.4 mg/kW'h), respectively.

Bloodletting Treatment of Hakjil(瘧疾) - A focus on the「Jahak(刺瘧)」 chapter of 『Hwangjenaegyeong(黃帝內經).Somun(素問)』- (학질(瘧疾)의 자락사혈(刺絡瀉血) 치료법(治療法)에 대한 고찰(考察) -『素問.刺瘧』을 중심으로-)

  • Kim, Dong-Hui;Jeong, Chang-Hyun;Jang, Woo-Chang;Lyu, Jeong-Ah;Baik, You-Sang
    • Journal of Korean Medical classics
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    • v.24 no.4
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    • pp.23-32
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    • 2011
  • The texts of "Hwangjenaegyeong(黃帝內經)" explains Hakjil(瘧疾) in detail, especially in the "Jahak(刺瘧)" chapter, where bloodletting treatment is applied in many cases. The following paper categorized and organized Hakjil(瘧疾) cases treated by bloodletting methods, then analyzed applicable subjects and appropriate time for the procedure based on the texts. Afterwards, the mechanism for the cessation of Hakjil(瘧疾) seizures was examined. The findings of this research are as follows. 1. In the contents of "Hwangjenaegyeong(黃帝內經)", the appropriate time for acupuncture and bloodletting procedure is when Hakjil(瘧疾) seizures start to present themselves. 2. When a seizure takes place as a symptom of the body getting rid of the Hak(瘧) pathogen, Yanggi(陽氣) rushes to the locus of the pathogen, causing congestion of Gi(氣) and Blood(血) resulting in static blood[瘀血]. Therefore, bloodletting at the time of seizure initiation helps the flow of Gi(氣) and Blood(血), preventing the rush of Yanggi(陽氣). This is a restoration of the balancing function of Eum(陰) and Yang(陽), which indicates that bloodletting not only promotes smooth flow of Gi(氣) and Blood(血), but extends its effects to mental functions that balances Eum(陰) and Yang(陽). 3. Although Hakjil(瘧疾) seizures are presented in terms of Gi(氣) and Blood(血) in symptoms such as chill and fever[寒熱], static blood[瘀血], pain, etc., a fundamental disturbance in mental functions that control cold and heat seems to be present.

Implementation of Electrical Performance Test Evaluation System for Car Fuel Heater (차량 연료히터의 전기적 성능시험 평가 시스템 구현)

  • Yoon, Dal-Hwan
    • Journal of IKEEE
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    • v.17 no.1
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    • pp.63-70
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    • 2013
  • In this paper, we have implemented the performance evaluation system of the unified fuel heater for CRDI diesel engine. If the diesel engine be cold by low temperature in winter, then that makes the waxing materials like a paraffin and is the source of poor engine starting. The unified fuel heater is the barrow meter that estimate the start performance of diesel engine, and be tested by test chamber. The chamber perform the normal temperature, an extremely low temperature, an operating performance in an extremely high temperature, the resistance operation delay time and current operation delay time in setting up test resistance, the bimetal delay time test in temperature variation, the current and resistor test of the composited heater, a heating operation test.

Clustering Method based on Genre Interest for Cold-Start Problem in Movie Recommendation (영화 추천 시스템의 초기 사용자 문제를 위한 장르 선호 기반의 클러스터링 기법)

  • You, Tithrottanak;Rosli, Ahmad Nurzid;Ha, Inay;Jo, Geun-Sik
    • Journal of Intelligence and Information Systems
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    • v.19 no.1
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    • pp.57-77
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    • 2013
  • Social media has become one of the most popular media in web and mobile application. In 2011, social networks and blogs are still the top destination of online users, according to a study from Nielsen Company. In their studies, nearly 4 in 5active users visit social network and blog. Social Networks and Blogs sites rule Americans' Internet time, accounting to 23 percent of time spent online. Facebook is the main social network that the U.S internet users spend time more than the other social network services such as Yahoo, Google, AOL Media Network, Twitter, Linked In and so on. In recent trend, most of the companies promote their products in the Facebook by creating the "Facebook Page" that refers to specific product. The "Like" option allows user to subscribed and received updates their interested on from the page. The film makers which produce a lot of films around the world also take part to market and promote their films by exploiting the advantages of using the "Facebook Page". In addition, a great number of streaming service providers allows users to subscribe their service to watch and enjoy movies and TV program. They can instantly watch movies and TV program over the internet to PCs, Macs and TVs. Netflix alone as the world's leading subscription service have more than 30 million streaming members in the United States, Latin America, the United Kingdom and the Nordics. As the matter of facts, a million of movies and TV program with different of genres are offered to the subscriber. In contrast, users need spend a lot time to find the right movies which are related to their interest genre. Recent years there are many researchers who have been propose a method to improve prediction the rating or preference that would give the most related items such as books, music or movies to the garget user or the group of users that have the same interest in the particular items. One of the most popular methods to build recommendation system is traditional Collaborative Filtering (CF). The method compute the similarity of the target user and other users, which then are cluster in the same interest on items according which items that users have been rated. The method then predicts other items from the same group of users to recommend to a group of users. Moreover, There are many items that need to study for suggesting to users such as books, music, movies, news, videos and so on. However, in this paper we only focus on movie as item to recommend to users. In addition, there are many challenges for CF task. Firstly, the "sparsity problem"; it occurs when user information preference is not enough. The recommendation accuracies result is lower compared to the neighbor who composed with a large amount of ratings. The second problem is "cold-start problem"; it occurs whenever new users or items are added into the system, which each has norating or a few rating. For instance, no personalized predictions can be made for a new user without any ratings on the record. In this research we propose a clustering method according to the users' genre interest extracted from social network service (SNS) and user's movies rating information system to solve the "cold-start problem." Our proposed method will clusters the target user together with the other users by combining the user genre interest and the rating information. It is important to realize a huge amount of interesting and useful user's information from Facebook Graph, we can extract information from the "Facebook Page" which "Like" by them. Moreover, we use the Internet Movie Database(IMDb) as the main dataset. The IMDbis online databases that consist of a large amount of information related to movies, TV programs and including actors. This dataset not only used to provide movie information in our Movie Rating Systems, but also as resources to provide movie genre information which extracted from the "Facebook Page". Formerly, the user must login with their Facebook account to login to the Movie Rating System, at the same time our system will collect the genre interest from the "Facebook Page". We conduct many experiments with other methods to see how our method performs and we also compare to the other methods. First, we compared our proposed method in the case of the normal recommendation to see how our system improves the recommendation result. Then we experiment method in case of cold-start problem. Our experiment show that our method is outperform than the other methods. In these two cases of our experimentation, we see that our proposed method produces better result in case both cases.

High Purity Hydrogen Generator for Fuel Cell Vehicles (연료전지 자동차 탑재형 고순도 수소생산장치)

  • Han, Jaesung;Lee, Seok-Min
    • Journal of Hydrogen and New Energy
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    • v.12 no.4
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    • pp.277-285
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    • 2001
  • We developed a compact, 10 kWe, purifier-integrated reformer which supplies hydrogen for fuel cell vehicles. Our proprietary technologies regarding hydrogen purification by palladium alloy membrane and catalytic combustion by noble metal coated wire-mesh catalyst were combined with the conventional methanol steam reforming technology, resulting in higher conversion, excellent quality of product hydrogen, and better thermal efficiency than any other systems. In this system, steam reforming, hydrogen purification, and catalytic combustion take place all in a single reactor so that the whole system is compact and easy to operate. The module produces $8.2Nm^3/hr$ of 99.999% or higher purity hydrogen with CO impurity less than 10 ppm, which is equivalent to 10 kWe when PEMFC has 45 % efficiency. Thermal efficiency of the module is 81 % and the power density of the module is 1.6 L/kWe. As the results of experiments, cold-start time has been measured about 20 minutes. Response time of hydrogen production to the change of the feed rate has been within 1 minutes.

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Incorporating Time Constraints into a Recommender System for Museum Visitors

  • Kovavisaruch, La-or;Sanpechuda, Taweesak;Chinda, Krisada;Wongsatho, Thitipong;Wisadsud, Sodsai;Chaiwongyen, Anuwat
    • Journal of information and communication convergence engineering
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    • v.18 no.2
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    • pp.123-131
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    • 2020
  • After observing that most tourists plan to complete their visits to multiple cultural heritage sites within one day, we surmised that for many museum visitors, the foremost thought is with regard to the amount of time is to be spent at each location and how they can maximize their enjoyment at a site while still balancing their travel itinerary? Recommendation systems in e-commerce are built on knowledge about the users' previous purchasing history; recommendation systems for museums, on the other hand, do not have an equivalent data source available. Recent solutions have incorporated advanced technologies such as algorithms that rely on social filtering, which builds recommendations from the nearest identified similar user. Our paper proposes a different approach, and involves providing dynamic recommendations that deploy social filtering as well as content-based filtering using term frequency-inverse document frequency. The main challenge is to overcome a cold start, whereby no information is available on new users entering the system, and thus there is no strong background information for generating the recommendation. In these cases, our solution deploys statistical methods to create a recommendation, which can then be used to gather data for future iterations. We are currently running a pilot test at Chao Samphraya national museum and have received positive feedback to date on the implementation.

Exercise Recommendation System Using Deep Neural Collaborative Filtering (신경망 협업 필터링을 이용한 운동 추천시스템)

  • Jung, Wooyong;Kyeong, Chanuk;Lee, Seongwoo;Kim, Soo-Hyun;Sun, Young-Ghyu;Kim, Jin-Young
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.22 no.6
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    • pp.173-178
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    • 2022
  • Recently, a recommendation system using deep learning in social network services has been actively studied. However, in the case of a recommendation system using deep learning, the cold start problem and the increased learning time due to the complex computation exist as the disadvantage. In this paper, the user-tailored exercise routine recommendation algorithm is proposed using the user's metadata. Metadata (the user's height, weight, sex, etc.) set as the input of the model is applied to the designed model in the proposed algorithms. The exercise recommendation system model proposed in this paper is designed based on the neural collaborative filtering (NCF) algorithm using multi-layer perceptron and matrix factorization algorithm. The learning proceeds with proposed model by receiving user metadata and exercise information. The model where learning is completed provides recommendation score to the user when a specific exercise is set as the input of the model. As a result of the experiment, the proposed exercise recommendation system model showed 10% improvement in recommended performance and 50% reduction in learning time compared to the existing NCF model.

Personal Information Protection Recommendation System using Deep Learning in POI (POI 에서 딥러닝을 이용한 개인정보 보호 추천 시스템)

  • Peng, Sony;Park, Doo-Soon;Kim, Daeyoung;Yang, Yixuan;Lee, HyeJung;Siet, Sophort
    • Annual Conference of KIPS
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    • 2022.11a
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    • pp.377-379
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    • 2022
  • POI refers to the point of Interest in Location-Based Social Networks (LBSNs). With the rapid development of mobile devices, GPS, and the Web (web2.0 and 3.0), LBSNs have attracted many users to share their information, physical location (real-time location), and interesting places. The tremendous demand of the user in LBSNs leads the recommendation systems (RSs) to become more widespread attention. Recommendation systems assist users in discovering interesting local attractions or facilities and help social network service (SNS) providers based on user locations. Therefore, it plays a vital role in LBSNs, namely POI recommendation system. In the machine learning model, most of the training data are stored in the centralized data storage, so information that belongs to the user will store in the centralized storage, and users may face privacy issues. Moreover, sharing the information may have safety concerns because of uploading or sharing their real-time location with others through social network media. According to the privacy concern issue, the paper proposes a recommendation model to prevent user privacy and eliminate traditional RS problems such as cold-start and data sparsity.

Temperature Changes of Climatic Solar Terms and Their Spatiotemporal Characteristics in South Korea (우리나라 기후 절기별 기온 변화의 시공간적 특성 분석)

  • Jin, Mi Jeong;Park, Sunyurp
    • Journal of the Korean Geographical Society
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    • v.50 no.1
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    • pp.23-36
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    • 2015
  • The temperature change patterns of climatic solar terms and their climatic fitness were analyzed. Harmonic analysis based on thirty-year(1981-2010) time-series data from sixty one weather stations across South Korea showed that the central peaks of the extreme heat had shifted toward start of autumn with increasing mean temperature. The overall climatic fitness of solar terms, such as major heat, frost descent, major snow, and major cold, was low, and it showed significant regional variations. The actual meteorological phenomenon representing each climatic solar term was observed much later than the day of the solar term at most weather stations. The number of observations, where an actual meteorological condition for each climatic solar term was recorded within ${\pm}1$ week from the day of that solar term, ranged only from 7.7% to 40.4% of the entire data. Study results also showed that the climatic fitness of major heat, frost descent, and major snow gradually changed in the east-west direction. Major cold, a solar term with higher climatic fitness, was influenced more strongly by latitude than longitude. Considering geographically uneven magnitude and trends in temperature changes, rearrangement and adjustment of time intervals between the solar terms may help us improve their applicability as realistic indicators of seasonal changes.

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