Masayuki Murata

Masayuki Murata
Osaka University | Handai · Graduate School of Information Science and Technology

Dr. Eng.

About

1,178
Publications
87,886
Reads
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10,039
Citations
Additional affiliations
September 1987 - present
Osaka University
April 1984 - August 1987
IBM Tokyo Research Laboratory
Position
  • Researcher

Publications

Publications (1,178)
Article
Full-text available
During ethanol fermentation, yeast cells are exposed to various stresses that have negative effects on cell growth, cell survival, and fermentation ability. This study, therefore, aims to develop Kluyveromyces marxianus-adapted strains that are multi-stress tolerant and to increase ethanol production at high temperatures through a novel evolutionar...
Article
Many new network-oriented services have been developed in recent years, and Multi-access Edge Computing (MEC) has been standardized to improve the responsiveness of services. When deploying services in a MEC environment, it is necessary to consider a service structure that can flexibly switch service behaviors to meet various user requests and that...
Article
The intrinsic mechanism of the thermotolerance of Kluyveromyces marxianus was investigated by comparison of its physiological and metabolic properties at high and low temperatures. After glucose consumption, the conversion of ethanol to acetic acid became gradually prominent only at high temperature (45°C) and eventually caused a decline in viabili...
Chapter
In Kluyveromyces marxianus, a thermotolerant yeast that has already been utilized for producing various useful materials, recent advances including complete genome sequencing and transcriptome analysis have provided valuable information on its physiological and metabolic characteristics including its capacity for assimilation of various sugars and...
Article
Full-text available
It is now becoming important for mobile cellular networks to accommodate all kinds of Internet of Things (IoT) communications. However, the contention-based random access and radio resource allocation used in traditional cellular networks, which are optimized mainly for human communications, cannot efficiently handle large-scale IoT communications....
Article
Full-text available
The combination of high-temperature fermentation and membrane separation has the potential to realize a simple on-site process to produce concentrated bioethanol. The performance of dehydration membranes in separating bioethanol was investigated in this study. Three types of zeolite membranes, LTA, MFI, and MOR, were synthesized. Their dehydration...
Preprint
We theoretically study the role of excitatory and inhibitory interactions in the aggregations of male frogs. In most frogs, males produce sounds to attract conspecific females, which activates the calling behavior of other males and results in collective choruses. While the calling behavior is quite effective for mate attraction, it requires high e...
Preprint
Full-text available
Internet-of-things (IoT) devices are vulnerable to malicious operations by attackers, which can cause physical and economic harm to users; therefore, we previously proposed a sequence-based method that modeled user behavior as sequences of in-home events and a base home state to detect anomalous operations. However, that method modeled users' home...
Article
Full-text available
To mitigate the risk of cyberattacks on home IoT devices, we have proposed a method for detecting anomalous operations by learning the behaviors of users based on the operation sequences of their home IoT devices and home conditions. While this method requires a sufficient amount of training data, achieving accurate detection is still possible by u...
Chapter
Machine learning (ML) models are often adopted in malware detection systems. To ensure the detection performance in such ML-based systems, updating ML models with new data is crucial for minimizing the influence of data variation over time. After an update, validating the new model is commonly done using the detection accuracy as a metric. However,...
Article
Full-text available
The SOS response is induced upon DNA damage and the inhibition of Z ring formation by the product of the sulA gene, which is one of the LexA-regulated genes, allows time for repair of damaged DNA. On the other hand, severely DNA-damaged cells are eliminated from cell populations. Overexpression of sulA leads to cell lysis, suggesting SulA eliminate...
Article
The term “flash crowd” describes a situation in which a large number of users access a Web service simultaneously. Flash crowds, in particular, constitute a critical problem in e-commerce applications because of the potential for enormous economic damage as well as difficulty in management. Flash crowds can become more serious depending on users' b...
Preprint
Full-text available
The spread of information networks has not only made it easier for people to access a variety of information sources but also greatly enhanced the ability of individuals to disseminate information. Unfortunately, however, the problem of slander in online social networks shows that the evolving information network environment does not necessarily su...
Conference Paper
Full-text available
The spread of information networks has not only made it easier for people to access a variety of information sources but also greatly enhanced the ability of individuals to disseminate information. Unfortunately, however, the problem of slander in online social networks shows that the evolving information network environment does not necessarily su...
Article
Full-text available
One of the models in the literature for modeling the behavior of the brain is the Bayesian attractor model, which is a kind of machine-learning algorithm. According to this model, the brain assigns stochastic variables to possible decisions (attractors) and chooses one of them when enough evidence is collected from sensory systems to achieve a conf...
Preprint
Full-text available
Securing the traceability of products in the supply chain is an urgent issue. Recently, supply chain systems that use public blockchain (PBC) have been proposed. In these systems, PBC is used as a common database shared between supply chain parties to secure the integrity and reliability of distribution information such as ownership transfer record...
Article
Full-text available
As several home appliances, such as air conditioners, heaters, and refrigerators, were connecting to the Internet, they became targets of cyberattacks, which cause serious problems such as compromising safety and even harming users. We have proposed a method to detect such attacks based on user behavior. This method models user behavior as sequence...
Article
Software-defined infrastructure (SDI) makes it possible to construct virtual networks with finer time granularity than was possible before, possibly allowing immediate responses to customer requests to increase or decrease resource levels to match demand. Adaptation by virtual network embedding (VNE) control is a promising technique for handling de...
Article
Full-text available
Thermotolerant genes, which are essential for survival at a high temperature, have been identified in three mesophilic microbes, including Zymomonas mobilis. Contrary to expectation, they include only a few genes for reactive oxygen species (ROS)-scavenging enzymes and heat shock proteins, which are assumed to play key roles at a critical high temp...
Article
Full-text available
Among the so-called non-conventional yeasts, Kluyveromyces marxianus has extremely potent traits that are suitable for industrial applications. Indeed, it has been used for the production of various enzymes, chemicals, and macromolecules in addition to utilization of cell biomass as nutritional materials, feed and probiotics. The yeast is expected...
Article
Full-text available
Network Function Virtualization (NFV) is a system that provides application services by connecting virtual network functions (VNFs), and is expected to accommodate new service requests through the development of new VNF and connection with existing ones. Because VNFs are implemented by software, their design and placement are important problems for...
Conference Paper
Managed security services detect incidents, i.e., successful attacks such as malware infection, in real time from a large number of alerts based on vendors' and security operations center's (SOC's) detection rules. To immediately find incidents, professional analysts in a SOC prioritize alerts if their indicators, i.e., meta-information of detectio...
Article
Full-text available
In realizing the network environment assumed by the Internet-of-Things, network slicing has drawn considerable attention as a way to enhance the utilization of physical networks (PNs). Meanwhile, slicing has been shown to cause interdependence among sliced virtual networks (VNs) by propagating traffic fluctuations from one network to others. Howeve...
Article
Full-text available
In the past, various optimization objective functions have been proposed to help in network optimization, especially for use in traffic engineering (TE) and topology optimization. This variety of optimization objectives resulted in the emergence of algorithms targeting different objectives. However, the role of the objective function has been large...
Article
Full-text available
The diagnosis and prognosis of patients with severe chronic disorders of consciousness are still challenging issues and a high rate of misdiagnosis is evident. Hence, new tools are needed for an accurate diagnosis, which will also have an impact on the prognosis. In recent years, functional Magnetic Resonance Imaging (fMRI) has been gaining more an...
Article
Full-text available
Kmmig1 as a disrupted mutant of MIG1 encoding a regulator for glucose repression in Kluyveromyces marxianus exhibits a histidine-auxotrophic phenotype. Genome-wide expression analysis revealed that only HIS4 in seven HIS genes for histidine biosynthesis was down-regulated in Kmmig1. Consistently, introduction of HIS4 into Kmmig1 suppressed the requ...
Preprint
Kmmig1 as a disrupted mutant of MIG1 encoding a regulator for glucose repression in Kluyveromyces marxianus exhibits a histidine-auxotrophic phenotype. Genome-wide expression analysis revealed that only HIS4 in seven HIS genes for histidine biosynthesis was down-regulated in Kmmig1. Consistently, introduction of HIS4 into Kmmig1 suppressed the requ...
Article
Full-text available
The Intergovernmental Panel on Climate Change recommends keeping the increase in temperature to less than a two-degree increase by the end of the century, but the direct impact of global warming on ecosystems including microbes has not been investigated. Here we performed thermal adaptation of two species and three strains of mesophilic microbes fo...
Data
Procedure for construction of mutators, 200MΔmutS and 200MΔmutL, and their mutation frequency. (A) An upstream DNA fragment including the coding sequence for the N-terminal portion of MutS and a downstream DNA fragment including the coding sequence for the C-terminal portion of MutS were separately amplified by PCR with the genomic DNA of TISTR 548...
Data
Comparison of acridine orange-stained cells and growth of thermoadapted mutants from W3110 with those of the parent. (A) Thermoadapted mutants, ImB2 and ImB4, from W3110 were grown at 47°C in LB medium and cells at the exponential phase were stained with acridine orange. (B) Cell growth was compared by cultivation at 37°C in LB medium. (PDF)
Data
Summary of mutations in thermoadapted mutants from Escherichia coli W3110. (PDF)
Data
Primers used for confirmation of mutation sites in coding regions of thermoadapted mutants from Z. mobilis TISTR548. (PDF)
Data
Primers used for confirmation of mutation sites in coding regions of thermoadapted mutants from E. coli W3110. (PDF)
Data
Two-step cultivation for determination of CHT. (A and B) Strains A and B are cultured in a rich medium at 37°C (A) and 38°C (B) as the first cultivation (straight lines). After 12 h, an aliquot of the culture is transferred to a fresh medium and subjected to the second cultivation (dotted lines). Strain B shows an increase in turbidity (OD550) at 3...
Data
Determination of CHT of Z. moblis CP4. (A) CHT of Z. moblis CP4 was determined by the two-step cultivation method as described in S1 Fig. (B and C) Using the culture of CP4 at 12 h in the first cultivation, a live and dead cell assay and determination of CFU were performed. (PDF)
Data
Summary of mutations in thermoadapted mutants from Zymomonas mobilis CP4. (PDF)
Data
Characteristics of thermoadapted mutants from CP4. (A) Comparison in the accumulation of ROS. Thermoadapted mutants, Z4-80a, Z4-80b, Z4-80c and Z4-80d, from CP4 were grown at 30°C, 36°C and 38°C in YPD medium. Using cells at the exponential phase, fluorescent intensity with H2DCFDA, which reflects accumulation of ROS, was measured. (B) Resistance t...
Data
Summary of mutations in thermoadapted mutants from Zymomonas mobilis TISTR548. (PDF)
Data
Primers used for construction of mutators. (PDF)
Data
Characteristics of thermoadapted mutants from TISTR548. (A) Effects of a high concentration of glucose and low pHs on growth of thermoadapted mutants from TISTR548. Mutants, 80M, 130M and 200M, and their parental strain were grown at 30°C in YPD medium until the exponential phase. The culture was serially diluted and spotted on pH 7-adjusted YP pla...
Data
List of sequencing data and platform used in this study. (PDF)
Data
Primers used for confirmation of mutation sites in coding regions of thermoadapted mutants from Z. mobilis CP4. (PDF)
Article
To provide video streaming of user-generated contents (UGCs) with high quality and at low cost by maximizing the effect of content delivery network (CDN), CDN providers are required to adequately design CDN cache servers by accurately estimating the UGC view-count distribution. To achieve this goal in a practical time frame, we need to construct a...
Article
In Network Functions Virtualization (NFV), network functions are operated in software as Virtual Network Functions (VNFs) instead of dedicated hardware. The most important issues that need to be addressed in NFV are where the VNFs should be placed in the network, as well as what amount of resources should be assigned to each VNF. Evolvable VNF Plac...
Article
Many users are exposed to threats of drive-by download attacks through the Web. Attackers compromise vulnerable websites discovered by search engines and redirect clients to malicious websites created with exploit kits. Security researchers and vendors have tried to prevent the attacks by detecting malicious data, i.e., malicious URLs, web content,...
Article
Information-centric networking (ICN), a new network architecture for efficiently delivering content, has been widely investigated recently. In ICN, cache memory is implemented at each router, and content items are routed in the network by using content name as the locator determining the destination. The caching strategy that determines the content...