• Title/Summary/Keyword: simultaneous access

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Early implant failure: a retrospective analysis of contributing factors

  • Kang, Dae-Young;Kim, Myeongjin;Lee, Sung-Jo;Cho, In-Woo;Shin, Hyun-Seung;Caballe-Serrano, Jordi;Park, Jung-Chul
    • Journal of Periodontal and Implant Science
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    • v.49 no.5
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    • pp.287-298
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    • 2019
  • Purpose: The aim of this retrospective study was to determine the prevalence of early implant failure using a single implant system and to identify the factors contributing to early implant failure. Methods: Patients who received implant treatment with a single implant system ($Luna^{(R)}$, Shinhung, Seoul, Korea) at Dankook University Dental Hospital from 2015 to 2017 were enrolled. The following data were collected for analysis: sex and age of the patient, seniority of the surgeon, diameter and length of the implant, position in the dental arch, access approach for sinus-floor elevation, and type of guided bone regeneration (GBR) procedure. The effect of each predictor was evaluated using the crude hazard ratio and the adjusted hazard ratio (aHR) in univariate and multivariate Cox regression analyses, respectively. Results: This study analyzed 1,031 implants in 409 patients, who comprised 169 females and 240 males with a median age of 54 years (interquartile range [IQR], 47-61 years) and were followed up for a median of 7.2 months (IQR, 5.6-9.9 months) after implant placement. Thirty-five implants were removed prior to final prosthesis delivery, and the cumulative survival rate in the early phase at the implant level was 95.6%. Multivariate regression analysis revealed that seniority of the surgeon (residents: aHR=2.86; 95% confidence interval [CI], 1.37-5.94) and the jaw in which the implant was placed (mandible: aHR=2.31; 95% CI, 1.12-4.76) exerted statistically significant effects on early implant failure after adjusting for sex, age, dimensions of the implant, and type of GBR procedure (preoperative and/or simultaneous) (P<0.05). Conclusions: Prospective studies are warranted to further elucidate the factors contributing to early implant failure. In the meantime, surgeons should receive appropriate training and carefully select the bone bed in order to minimize the risk of early implant failure.

DRAZ: SPARQL Query Engine for heterogeneous metadata sources (DRAZ : 이기종 메타 데이터 소스를 위한 SPARQL 쿼리 엔진)

  • Qudus, UMAIR;Hossain, Md Ibrahim;Lee, ChangJu;Khan, Kifayat Ullah;Won, Heesun;Lee, Young-Koo
    • Database Research
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    • v.34 no.3
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    • pp.69-85
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    • 2018
  • Many researches proposed federated query engines to perform query on several homogeneous or heterogeneous datasets simultaneously that significantly improve the quality of query results. The existing techniques allow querying only over a few heterogeneous datasets considering the static binding using the non-standard query. However, we observe that a simultaneous system considering the integration of heterogeneous metadata standards can offer better opportunity to generalize the query over any homogeneous and heterogeneous datasets. In this paper, we propose a transparent federated engine (DRAZ) to query over multiple data sources using SPARQL. In our system, we first develop the ontology for a non-RDF metadata standard based on the metadata kernel dictionary elements, which are standardized by the metadata provider. For a given SPARQL query, we translate any triple pattern into an API call to access the dataset of corresponding non-RDF metadata standard. We convert the results of every API call to N-triples and summarize the final results considering all triple patterns. We evaluated our proposed DRAZ using modified Fedbench benchmark queries over heterogeneous metadata standards, such as DCAT and DOI. We observed that DRAZ can achieve 70 to 100 percent correctness of the results despite the unavailability of the JOIN operations.

GPU-based Parallel Ant Colony System for Traveling Salesman Problem

  • Rhee, Yunseok
    • Journal of the Korea Society of Computer and Information
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    • v.27 no.2
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    • pp.1-8
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    • 2022
  • In this paper, we design and implement a GPU-based parallel algorithm to effectively solve the traveling salesman problem through an ant color system. The repetition process of generating hundreds or thousands of tours simultaneously in TSP utilizes GPU's task-level parallelism, and the update process of pheromone trails data actively exploits data parallelism by 32x32 thread blocks. In particular, through simultaneous memory access of multiple threads, the coalesced accesses on continuous memory addresses and concurrent accesses on shared memory are supported. This experiment used 127 to 1002 city data provided by TSPLIB, and compared the performance of sequential and parallel algorithms by using Intel Core i9-9900K CPU and Nvidia Titan RTX system. Performance improvement by GPU parallelization shows speedup of about 10.13 to 11.37 times.

Mobile Robot Localization in Geometrically Similar Environment Combining Wi-Fi with Laser SLAM

  • Gengyu Ge;Junke Li;Zhong Qin
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.17 no.5
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    • pp.1339-1355
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    • 2023
  • Localization is a hot research spot for many areas, especially in the mobile robot field. Due to the weak signal of the global positioning system (GPS), the alternative schemes in an indoor environment include wireless signal transmitting and receiving solutions, laser rangefinder to build a map followed by a re-localization stage and visual positioning methods, etc. Among all wireless signal positioning techniques, Wi-Fi is the most common one. Wi-Fi access points are installed in most indoor areas of human activities, and smart devices equipped with Wi-Fi modules can be seen everywhere. However, the localization of a mobile robot using a Wi-Fi scheme usually lacks orientation information. Besides, the distance error is large because of indoor signal interference. Another research direction that mainly refers to laser sensors is to actively detect the environment and achieve positioning. An occupancy grid map is built by using the simultaneous localization and mapping (SLAM) method when the mobile robot enters the indoor environment for the first time. When the robot enters the environment again, it can localize itself according to the known map. Nevertheless, this scheme only works effectively based on the prerequisite that those areas have salient geometrical features. If the areas have similar scanning structures, such as a long corridor or similar rooms, the traditional methods always fail. To address the weakness of the above two methods, this work proposes a coarse-to-fine paradigm and an improved localization algorithm that utilizes Wi-Fi to assist the robot localization in a geometrically similar environment. Firstly, a grid map is built by using laser SLAM. Secondly, a fingerprint database is built in the offline phase. Then, the RSSI values are achieved in the localization stage to get a coarse localization. Finally, an improved particle filter method based on the Wi-Fi signal values is proposed to realize a fine localization. Experimental results show that our approach is effective and robust for both global localization and the kidnapped robot problem. The localization success rate reaches 97.33%, while the traditional method always fails.

Endovascular Treatment of a Systemic-to-Pulmonary Artery Fistula: A Case Report (체-폐동맥루의 혈관 내 치료: 증례 보고)

  • Eunbyul Lee;Dong Jae Shim;Doyoung Kim;Jung Whee Lee
    • Journal of the Korean Society of Radiology
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    • v.82 no.3
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    • pp.682-687
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    • 2021
  • Systemic-to-pulmonary artery fistulas are rare. This condition may be congenital, post-traumatic, or post-inflammatory and can cause infection, hemorrhage, or pulmonary hypertension. Here, we report a case of an intercostal-to-pulmonary artery fistula, incidentally detected during the evaluation of dyspnea in a 67-year-old female. Retrograde transcatheter coil embolization in a dilated draining pulmonary artery was initially attempted. However, another draining pulmonary artery developed after 5 months. The intercostal arteries or systemic feeders were successfully embolized through a transarterial access. At the 10-month follow-up, the abnormally dilated vessels had regressed, and dyspnea had improved. Sequential or simultaneous retro- and antegrade transcatheter embolization may successfully treat pleural arterio-arterial fistulas.

Intelligent Brand Positioning Visualization System Based on Web Search Traffic Information : Focusing on Tablet PC (웹검색 트래픽 정보를 활용한 지능형 브랜드 포지셔닝 시스템 : 태블릿 PC 사례를 중심으로)

  • Jun, Seung-Pyo;Park, Do-Hyung
    • Journal of Intelligence and Information Systems
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    • v.19 no.3
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    • pp.93-111
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    • 2013
  • As Internet and information technology (IT) continues to develop and evolve, the issue of big data has emerged at the foreground of scholarly and industrial attention. Big data is generally defined as data that exceed the range that can be collected, stored, managed and analyzed by existing conventional information systems and it also refers to the new technologies designed to effectively extract values from such data. With the widespread dissemination of IT systems, continual efforts have been made in various fields of industry such as R&D, manufacturing, and finance to collect and analyze immense quantities of data in order to extract meaningful information and to use this information to solve various problems. Since IT has converged with various industries in many aspects, digital data are now being generated at a remarkably accelerating rate while developments in state-of-the-art technology have led to continual enhancements in system performance. The types of big data that are currently receiving the most attention include information available within companies, such as information on consumer characteristics, information on purchase records, logistics information and log information indicating the usage of products and services by consumers, as well as information accumulated outside companies, such as information on the web search traffic of online users, social network information, and patent information. Among these various types of big data, web searches performed by online users constitute one of the most effective and important sources of information for marketing purposes because consumers search for information on the internet in order to make efficient and rational choices. Recently, Google has provided public access to its information on the web search traffic of online users through a service named Google Trends. Research that uses this web search traffic information to analyze the information search behavior of online users is now receiving much attention in academia and in fields of industry. Studies using web search traffic information can be broadly classified into two fields. The first field consists of empirical demonstrations that show how web search information can be used to forecast social phenomena, the purchasing power of consumers, the outcomes of political elections, etc. The other field focuses on using web search traffic information to observe consumer behavior, identifying the attributes of a product that consumers regard as important or tracking changes on consumers' expectations, for example, but relatively less research has been completed in this field. In particular, to the extent of our knowledge, hardly any studies related to brands have yet attempted to use web search traffic information to analyze the factors that influence consumers' purchasing activities. This study aims to demonstrate that consumers' web search traffic information can be used to derive the relations among brands and the relations between an individual brand and product attributes. When consumers input their search words on the web, they may use a single keyword for the search, but they also often input multiple keywords to seek related information (this is referred to as simultaneous searching). A consumer performs a simultaneous search either to simultaneously compare two product brands to obtain information on their similarities and differences, or to acquire more in-depth information about a specific attribute in a specific brand. Web search traffic information shows that the quantity of simultaneous searches using certain keywords increases when the relation is closer in the consumer's mind and it will be possible to derive the relations between each of the keywords by collecting this relational data and subjecting it to network analysis. Accordingly, this study proposes a method of analyzing how brands are positioned by consumers and what relationships exist between product attributes and an individual brand, using simultaneous search traffic information. It also presents case studies demonstrating the actual application of this method, with a focus on tablets, belonging to innovative product groups.

Detecting Shared Resource Usage Errors with Global Predicates (광역조건식에 의한 공유자원 접근오류 검색)

  • Lee, Eun-Jeong;Yun, Gi-Jung
    • Journal of KIISE:Software and Applications
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    • v.26 no.12
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    • pp.1445-1454
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    • 1999
  • 광역 조건식의 계산은 분산 프로그램의 수행을 테스트 또는 디버깅하기 위한 방법으로 활 발히 연구되고 있다. 이제까지 주로 연구된 광역조건식은 AND 또는 OR 광역 조건식 등이 있는데, 특히 AND 광역 조건식은 분산 프로그램의 동시적 조건을 표현하는데 유용하여 효율적인 검색 알고리즘이 활발히 연구되었다. 분산프로그램의 수행오류로서 공유자원의 배타적 접근조건은 가장 중요하고 일반적인 경우라 할 수 있다. 본 논문에서는 XOR 연산을 이용하여 공유자원 프로그램의 오류 검색을 위한 광역조건식을 기술하는 방식에 대해 제안하였다. XOR 연산을 이용한 광역 조건식은 연산자 중 많아야 하나의 지역조건식만이 참일 때 전체 조건식이 참이 되는데 이러한 성질은 여러 프로세스 중 한번에 하나만이 공유자원에 배타적으로 접근할 수 있는 조건을 표현하는데 매우 유용하다. n 개의 프로세스로 이루어진 분산프로그램에서 한개의 공유자원에 대한 배타적 접근 조건을 기술하기 위해서 AND로 연결된 광역조건식을 이용하면 O(n2)개의 광역 조건식이 필요한데 반해 XOR 연산으로는 하나의 조건식으로 나타낼 수 있다. 더구나 XOR 연산을 이용한 광역조건식은 최근 소개된 겹치는 구간의 개념을 활용하면 매우 간단하게 검색할 수 있다. 본 논문에서는 겹치는 구간을 찾는 검색 알고리즘을 소개하고 증명하였다.Abstract Detecting global predicates is an useful tool for debugging and testing a distributed program. Past research has considered several restricted forms of predicates, including conjunctive or disjunctive form of predicates. Especially, conjunctive predicates have attracted main attention not only because they are useful to describe simultaneous conditions in a distributed program, but also because it is possible to find algorithms to evaluate them within reasonable time bound. Detecting errors in accessing shared resources are the most popular and important constraints of distributed programs. In this paper, we introduced an exclusive OR predicates as a model of global predicates to describe shared resource conditions in distributed programs. An exclusive OR predicate holds only when at most one operand is true, which is useful to describe mutual exclusion conditions of distributed programs where only one process should be allowed to access the shared resource at a time. One exclusive OR predicate is enough to describe mutual exclusion condition of n processes with one shared resource, while it takes O(n2) conjunctive predicates. Moreover, exclusive OR condition is easily detectable using the concept of overlapping intervals introduced by Venkatesan and Dathan. An off-line algorithm for evaluating exclusive OR global predicates is presented with a correctness proof.

Cellulosic Ethanol as Renewable Alternative Fuel (신재생 대안 에너지로서의 셀룰로스 에탄올)

  • Cho, Woo-Suk;Chung, Yu-Hee;Kim, Bo-Kyung;Suh, Su-Jeoung;Koh, Wan-Soo;Choe, Sung-Hwa
    • Journal of Plant Biotechnology
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    • v.34 no.2
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    • pp.111-118
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    • 2007
  • Global warming crisis due primarily to continued green house gas emission requires impending change to renewable alternative energy than continuously depending on exhausting fossil fuels. Bioenergy including biodiesel and bioethanol are considered good alternatives because of their renewable and sustainable nature. Bioethanol is currently being produced by using sucrose from sugar beet, grain starches or lignocellulosic biomass as sources of ethanol fermentation. However, grain production requires significant amount of fossil fuel inputs during agricultural practices, which means less competitive in reducing the level of green house gas emission. By contrast, cellulosic bioethanol can use naturally-growing, not-for-food biomass as a source of ethanol fermentation. In this respect, cellulosic ethanol than grain starch ethanol is considered a more appropriate as a alternative renewable energy. However, commercialization of cellulosic ethanol depends heavily on technology development. Processes such as securing enough biomass optimized for economic processing, pretreatment technology for better access of polymer-hydrolyzing enzymes, saccharification of recalcitrant lignocellulosic materials, and simultaneous fermentation of different sugars including 6-carbon glucose as well as 5-carbon xylose or arabinose waits for greater improvement in technologies. Although it seems to be a long way to go until commercialization, it should broadly benefit farmers with novel source of income, environment with greener and reduced level of global warming, and national economy with increased energy security. Mission-oriented strategies for cellulosic ethanol development participated by government funding agency and different disciplines of sciences and technologies should certainly open up a new era of renewable energy.

Technique for Placing Continuous Media on a Disk Array under Fault-Tolerance and Arbitrary-Rate Search (결함허용과 임의 속도 탐색을 고려한 연속 매체 디스크 배치 기법)

  • O, Yu-Yeong;Kim, Seong-Su;Kim, Jae-Hun
    • Journal of KIISE:Computer Systems and Theory
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    • v.26 no.9
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    • pp.1166-1176
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    • 1999
  • 연속 매체, 특히 비디오 데이타에 대한 일반 사용자 연산에는 재생뿐만 아니라 임의 속도 탐색 연산, 정지 연산, 그리고 그 외 다양한 연산이 있다. 이 연산 중에서 원하는 화면을 빨리 찾는 데에 유용한 고속 전진(FF: fast-forward)과 고속 후진(FB: fast-backward)은 재생 연산과는 달리 비순차적인 디스크 접근을 요구한다. 이러한 경우에 디스크 부하가 균등하지 않으면 일부 디스크에 접근이 편중되어 서비스 품질이 떨어진다. 본 논문에서는 디스크 배열을 이용한 저장 시스템에서 디스크 접근을 고르게 분산시키기 위하여 '소수 라운드 로빈(PRR: Prime Round Robin)' 방식으로 연속 매체를 디스크에 배치하는 기법에서 문제가 됐던 낭비된 디스크 저장 공간을 신뢰도 향상을 위해서 사용하는 '그룹화된 패리티를 갖는 소수 라운드 로빈(PRRgp: PRR with Grouped Parities)' 방식을 제안한다. 이 기법은 PRR 기법처럼 임의 속도 검색 연산에 있어서 디스크 배열을 구성하는 모든 디스크의 부하를 균등하게 할뿐만 아니라 낭비됐던 디스크 저장 공간에 신뢰도를 높이기 위한 패리티 정보를 저장함으로서 신뢰도를 향상시킬 수 있다. 신뢰도 모델링 방법으로 조합 모델과 마르코프 모델을 이용해서 결함발생율과 결함복구율을 고려한 신뢰도를 산출하고 비교.분석한다. PRR 기법으로 연속 매체를 저장하고 낭비되는 공간에 패리티 정보를 저장할 경우에 동시에 두 개 이상의 결함 발생 시에 그 결함으로부터 복구가 불가능하지만 PRRgp 기법에서는 약 30% 이상의경우에 대해서 동시에 두 개의 결함 발생 시에 저장한 패리티 정보를 이용한 복구가 가능할 뿐만 아니라 패리티 그룹의 수가 두 개 이상인 경우에는 두 개 이상의 결함에 대해서도 복구가 가능하다.Abstract End-user operations on continuous media (say video data) consist of arbitrary-rate search, pause, and others as well as normal-rate play. FF(fast-forward) / FB(fast-backward) among those operations are desirable to find out the scene of interest but they require non-sequential access of disks. When accesses are clustered to several disks without considering load balance, high quality services in playback may not be available. In this paper, we propose a new disk placement scheme, called PRRgp(Prime Round Robin with Grouped Parities), with enhanced reliability by using the wasted disk storage space in an old one(PRR: Prime Round Robin), in which continuous media are placed on a disk array based storage systems to distribute disk accesses uniformly. The PRRgp can not only achieve load balance of disks consisting of a disk array under arbitrary-rate search like PRR, but also improve reliability by storing parity information on the wasted disk space appropriately. We use combinatorial and Markov models to evaluate the reliability for a disk array and to analyze the results. When continuous media like PRR are placed and parity information on the wasted disk space is stored, we cannot tolerate more than two simultaneous faults. But they can be recovered by using stored parity information for about 30 percent as a whole in case of PRRgp presented in this paper. In addition, more than two faults can be tolerated in case there are more than two parity groups.

A Case of Pulmonary Hypertension Associated with Portal Hypertension (문맥고혈압에 동반된 폐고혈압 1예)

  • Jun, Byung-Min;Shin, Young-Rok;Kim, Eun-Kyung;Kim, Hyun-Young;Hong, Sang-Bum;Shim, Tae-Sun;Lim, Chae-Man;Koh, Youn-Suck;Kim, Woo-Sung;Kim, Dong-Soon;Kim, Won-Dong;Lee, Sang-Do
    • Tuberculosis and Respiratory Diseases
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    • v.48 no.1
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    • pp.67-71
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    • 2000
  • Since its first description in 1951 by Mantz and Craig, pulmonary hypertension associated with portal hypertension has been observed more frequently. In a recent prospective study Hadengue et al. reported 2 % incidence of pulmonary hypertension in patients with portal hypertension. Thus this simultaneous occurrence can no longer be considered to be coincidental. The etiology remains unclear. It is most likely that vasoactive substances, normally metabolized by the liver, may have gained access to pulmonary circulation through portosystemic collaterals in portal hypertension. In genetically susceptible individuals, these substances could lead to pulmonary hypertension by inducing vasoconstriction or direct toxic damage to the wall of the small pulmonary arteries. A recent case of pulmonary hypertension in a 49-year-old woman with portal hypertension due to liver cirrhosis is reported as well as a review of the literature.

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