Hiroaki Kikuchi

Prof. Hiroaki Kikuchi


Research Focus & Metrics

Academic Career Length

24Years (2003-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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8 November 2019 in International Journal of Information Security
Verified
Journal Article
Closed access
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Chun-I FanChun-I Fan
Chun-I Fan
YTYi-Fan Tseng
Yi-Fan Tseng
HSHui-Po Su
Hui-Po Su
RHRuei-Hau Hsu
Ruei-Hau Hsu
HKHiroaki Kikuchi
Hiroaki Kikuchi

28 March 2024 in Applied Sciences
Verified
Journal Article
Open access
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Andres Hernandez-MatamorosAndres Hernandez-Matamoros
Andres Hernandez-Matamoros
HKHiroaki Kikuchi
Hiroaki Kikuchi
In the rapidly evolving landscape of healthcare technology, the critical need for robust privacy safeguards is undeniable. Local Differential Privacy (LDP) offers a potential solution to address privacy concerns in data-rich industries. However, challenges such as the curse of dimensionality arise when dealing with multidimensional data. This is particularly pronounced in k-way joint probability estimation, where higher values of k lead to decreased accuracy. To overcome these challenges, we propose the integration of Bayesian Ridge Regression (BRR), known for its effectiveness in handling multicollinearity. Our approach demonstrates robustness, manifesting a noteworthy reduction in average variant distance when compared to baseline algorithms such as LOPUB and LOCOP. Additionally, we leverage the R-squared metric to highlight BRR’s advantages, illustrating its performance relative to LASSO, as LOPUB and LOCOP are based on it. This paper addresses a relevant concern related to datasets exhibiting high correlation between attributes, potentially allowing the extraction of information from one attribute to another. We convincingly show the superior performance of BRR over LOPUB and LOCOP across 15 datasets with varying average correlation attributes. Healthcare takes center stage in this collection of datasets. Moreover, the datasets explore diverse fields such as finance, travel, and social science. In summary, our proposed approach consistently outperforms the LOPUB and LOCOP algorithms, particularly when operating under smaller privacy budgets and with datasets characterized by lower average correlation attributes. This signifies the efficacy of Bayesian Ridge Regression in enhancing privacy safeguards in healthcare technology.


22 July 2024 in Applied Sciences
Verified
Journal Article
Open access
PDF file
HHHikaru Horigome
Hikaru Horigome
HKHiroaki Kikuchi
Hiroaki Kikuchi
MFMasahiro Fujita
Masahiro Fujita
Chia-Mu YuChia-Mu Yu
Chia-Mu Yu
Local differential privacy (LDP) protects user information from potential threats by randomizing data on individual devices before transmission to untrusted collectors. This method enables collectors to derive user statistics by analyzing randomized data, thereby presenting a promising avenue for privacy-preserving data collection. In the context of key–value data, in which discrete and continuous values coexist, PrivKV has been introduced as an LDP protocol to ensure secure collection. However, this framework is susceptible to poisoning attacks. To address this vulnerability, we propose an expectation maximization (EM)-based algorithm combined with a cryptographic protocol to facilitate secure random sampling. Our LDP protocol, known as emPrivKV, exhibits two key advantages: it improves the accuracy of statistical information estimation from randomized data, and enhances resilience against the manipulation of statistics, that is, poisoning attacks. These attacks involve malicious users manipulating the analysis results without detection. This study presents the empirical results of applying the emPrivKV protocol to both synthetic and open datasets, highlighting a notable improvement in the precision of statistical value estimation and robustness against poisoning attacks. As a result, emPrivKV improved the frequency and the mean gains by 17.1% and 25.9%, respectively, compared to PrivKV, with the number of fake users being 0.1 of the genuine users. Our findings contribute to the ongoing discourse on refining LDP protocols for key–value data in scenarios involving privacy-sensitive information.

22 September 2016
Verified
Book Chapter
Closed access
PDF file
HKHiroaki Kikuchi
Hiroaki Kikuchi
TYTakayasu Yamaguchi
Takayasu Yamaguchi
KHKoki Hamada
Koki Hamada
YYYuji Yamaoka
Yuji Yamaoka
HOHidenobu Oguri
Hidenobu Oguri
JSJun Sakuma
Jun Sakuma

2 January 2003
Verified
Conference Paper
Closed access
HKHiroaki Kikuchi
Hiroaki Kikuchi
TMT. Morishita
T. Morishita
MMM. Mukaidono
M. Mukaidono