著者
Hideki Kakeya Yoshihisa Matsumoto
出版者
Information Processing Society of Japan
雑誌
IPSJ Transactions on Bioinformatics (ISSN:18826679)
巻号頁・発行日
vol.15, pp.22-29, 2022 (Released:2022-11-16)
参考文献数
35

A method to find a probability that a given bias of mutations occur naturally is proposed to test whether a newly detected virus is a product of natural evolution or a product of non-natural process such as genetic manipulation. The probability is calculated based on the neutral theory of molecular evolution and binominal distribution of non-synonymous (N) and synonymous (S) mutations. Though most of the conventional analyses, including dN/dS analysis, assume that any kinds of point mutations from a nucleotide to another nucleotide occurs with the same probability, the proposed model takes into account the bias in mutations, where the equilibrium of mutations is considered to estimate the probability of each mutation. The proposed method is applied to evaluate whether the Omicron variant strain of SARS-CoV-2, whose spike protein includes 29 N mutations and only one S mutation, can emerge through natural evolution. The result of binomial test based on the proposed model shows that the bias of N/S mutations in the Omicron spike can occur with a probability of 2.0 × 10-3 or less. Even with the conventional model where the probabilities of any kinds of mutations are all equal, the strong N/S mutation bias in the Omicron spike can occur with a probability of 3.7 × 10-3, which means that the Omicron variant is highly likely a product of non-natural process including artifact.
著者
Songpon Teerakanok Tetsutaro Uehara Atsuo Inomata
出版者
Information Processing Society of Japan
雑誌
Journal of Information Processing (ISSN:18826652)
巻号頁・発行日
vol.29, pp.381-391, 2021 (Released:2021-05-15)
参考文献数
12
被引用文献数
1

In this paper, a generic framework for IoT device registration is proposed. Unlike existing approaches, the proposed method is designed to provide a high level of compatibility, allowing it to work well with devices from different manufacturers. Furthermore, this framework requires only some commonly available technologies (like Bluetooth or BLE) to perform, making it highly applicable to most of the current generation of smart devices available in the market. With security and user-friendliness in mind, the developed registration protocol requires less user interaction while maintaining a considerable high level of security against various types of attacks, i.e., eavesdropping, replay attacks, modification, and man-in-the-middle attack.
著者
Nobuaki Yasuo Keisuke Watanabe Hideto Hara Kentaro Rikimaru Masakazu Sekijima
出版者
Information Processing Society of Japan
雑誌
IPSJ Transactions on Bioinformatics (ISSN:18826679)
巻号頁・発行日
vol.11, pp.41-47, 2018 (Released:2018-12-10)
参考文献数
36
被引用文献数
4

Lead optimization is an essential step in drug discovery in which the chemical structures of compounds are modified to improve characteristics such as binding affinity, target selectivity, physicochemical properties, and toxicity. We present a concept for a computational compound optimization system that outputs optimized compounds from hit compounds by using previous lead optimization data from a pharmaceutical company. In this study, to predict the drug-likeness of compounds in the evaluation function of this system, we evaluated and compared the ability to correctly predict lead optimization strategies through learning to rank methods.
著者
Naoki Kobayakawa Mitsuyoshi Imamura Kei Nakagawa Kenichi Yoshida
出版者
Information Processing Society of Japan
雑誌
Journal of Information Processing (ISSN:18826652)
巻号頁・発行日
vol.28, pp.650-657, 2020 (Released:2020-09-15)
参考文献数
28

Open source software (OSS) has become indispensable to our society. The success of OSS depends on the participation of a large number of developers or maintainers (contributors). Shedding light on the mechanisms of their participation has been an important academic and practical matter. One aspect to decide participation is the future prospects of a project. However, the causal mechanism behind participation has yet to be studied exhaustively and remains unclear. In this study, we used cryptocurrency projects, many of them were developed on GitHub, to better understand this mechanism. Both GitHub and cryptocurrencies are highly transparent, i.e., information is fully disclosed; we can analyze relevant information on a project, such as the contributors' activities, financial information, and development status. We adopted market capitalization as the substitution index of future prospects and the number of contributors and analyzed the relationship using time series analysis techniques, such as the Granger causality test and regression. We found that the number of contributors increases two months after market capitalization increases. This quantifies the impact of the future prospects of the project, i.e., of the market capitalization of a cryptocurrency, on the participation of contributors.
著者
Tomoya Kitani
出版者
Information Processing Society of Japan
雑誌
Journal of Information Processing (ISSN:18826652)
巻号頁・発行日
vol.28, pp.3-15, 2020 (Released:2020-01-15)
参考文献数
41

In this paper, we describe the current situation of the motorcycle industry, the world's markets, and the trend of motorcycle researches. The purpose is to promote researches and developments of motorcycles so that motorcycles become safer and more convenient, and people will obtain good user-experiences (UX) with their motorcycle in their life. We summarize the current research issues and the current social issues about motorcycles, and then we introduce a solution for them with informatics and its related science and engineering. To make a motorcycle safer and to enhance its mobility, it is essential to investigate the motorcycle dynamics. The motion of a rider is also essential, and it affects the motorcycle motion, whereas the motion of a car driver seldom affects the car motion. It is because the weight of a rider is large enough, comparing to the weight of a motorcycle, and a rider usually moves widely to operate the motorcycle. In order to investigate the dynamics of the motorcycle system, which consists of a motorcycle itself and a rider, it is required to obtain appropriate sensing data of both the motorcycle and the rider to improve the knowledge of the dynamics by the data. Such data and knowledge can be applied to other applications and services such as sensing road traffic conditions. In this paper, we introduce the concept of the research project, Bikeinformatics, and the capability of GNSS precise positioning to append adequate labels to measured data with low-cost sensors.
著者
Xuping Huang Nobutaka Ono Akira Nishimura Isao Echizen
出版者
Information Processing Society of Japan
雑誌
Journal of Information Processing (ISSN:18826652)
巻号頁・発行日
vol.25, pp.469-476, 2017 (Released:2017-07-15)
参考文献数
28
被引用文献数
4

Reversible audio information hiding and sample-scanning methods are proposed for digital audio content to achieve detailed detection and localization of tampered positions in each frame. The method proposed in this study allows detecting multiple tampering and reusing reliable content as well as avoiding false detection which were impossible for other methods to simultaneously achieve. In the proposed method, the original signal is partitioned into fixed-length frames and then transformed into discrete cosine transform (DCT) coefficients by the integer modified DCT (intDCT). Expansion of the DCT coefficients is applied to embed a content-based hash as a payload. The integer DCT algorithm ensures the reversibility of the transform so that the original data and embedded payload can be perfectly restored to enable blind verification of the data integrity. The perceptual evaluation of speech quality (PESQ) with the listening quality objective mean opinion (MOSLQO), the segmental signal to noise ratio (segSNR), and subjective evaluation results show that the proposed algorithm provides good sound quality (MOSLQO and segSNR are respectively 4.41 and 23.31dB on average for a capacity of 8, 000bps). Detection and localization are accurate in terms of correctly localizing tampered frames in case of insertion or deletion.
著者
Takayuki Miyazaki Yasuhiko Minamide
出版者
Information Processing Society of Japan
雑誌
Journal of Information Processing (ISSN:18826652)
巻号頁・発行日
vol.27, pp.422-430, 2019 (Released:2019-06-15)
参考文献数
22
被引用文献数
1

Lookahead is an extension of regular expressions that has been adopted in many implementations and is widely used. Lookahead represents what is allowed as the rest of input. Morihata developed a conversion from regular expressions with lookahead (REwLA) to deterministic finite automata by extending Thompson's construction. In this paper, we develop a conversion from REwLA to deterministic finite automata by extending derivatives of regular expressions. First, we formalize the semantics of REwLA. An REwLA has information about the rest of the input, so the definition of the semantics of REwLA is not languages but structures different from those of regular expressions. Thus, we introduce languages with lookahead as sets of pairs of strings with several operations and define the semantics of REwLA as languages with lookahead. Next, we define two kinds of left quotient for languages with lookahead and give corresponding derivatives. Then, we show that the types of expressions obtained by repeatedly applying derivatives are finite under some equivalence relation and give a conversion to deterministic finite automata. We also show that the semantics of REwLA is a finite union of sets of the form A × B, where A and B are regular languages.
著者
Bektur Ryskeldiev Michael Cohen Jens Herder
出版者
Information Processing Society of Japan
雑誌
Journal of Information Processing (ISSN:18826652)
巻号頁・発行日
vol.26, pp.177-185, 2018 (Released:2018-02-15)
参考文献数
34
被引用文献数
7

We present a system that exploits mobile rotational tracking and photospherical imagery to allow users to share their environment with remotely connected peers “on the go.” We surveyed related interfaces and developed a unique groupware application that shares a mixed reality space with spatially-oriented live video feeds. Users can collaborate through realtime audio, video, and drawings in a virtual space. The developed system was tested in a preliminary user study, which confirmed an increase in spatial and situational awareness among viewers as well as reduction in cognitive workload. Believing that our system provides a novel style of collaboration in mixed reality environments, we discuss future applications and extensions of our prototype.
著者
Neda Gholami Mohammad Mahdi Dehshibi Andrew Adamatzky Antonio Rueda-Toicen Hector Zenil Mahmood Fazlali David Masip
出版者
Information Processing Society of Japan
雑誌
Journal of Information Processing (ISSN:18826652)
巻号頁・発行日
vol.28, pp.161-168, 2020 (Released:2020-02-15)
参考文献数
21
被引用文献数
1

For reconstructing CT images in the clinical setting, ‘effective energy’ is usually used instead of the total X-ray spectrum. This approximation causes an accuracy decline. We proposed to quantize the total X-ray spectrum into irregular intervals to preserve accuracy. A phantom consisting of the skull, rib bone, and lung tissues was irradiated with CT configuration in GATE/GEANT4. We applied inverse Radon transform to the obtained Sinogram to construct a Pixel-based Attenuation Matrix (PAM). PAM was then used to weight the calculated Hounsfield unit scale (HU) of each interval's representative energy. Finally, we multiplied the associated normalized photon flux of each interval to the calculated HUs. The performance of the proposed method was evaluated in the course of Complexity and Visual analysis. Entropy measurements, Kolmogorov complexity, and morphological richness were calculated to evaluate the complexity. Quantitative visual criteria (i.e., PSNR, FSIM, SSIM, and MSE) were reported to show the effectiveness of the fuzzy C-means approach in the segmenting task.
著者
Hiroaki Tanaka Yu Suzuki Shotaro Yamasaki Koichiro Yoshino Ko Kato Satoshi Nakamura
出版者
Information Processing Society of Japan
雑誌
IPSJ Transactions on Bioinformatics (ISSN:18826679)
巻号頁・発行日
vol.11, pp.14-23, 2018 (Released:2018-07-05)
参考文献数
43

Protein production in plants is a hot topic because there are many benefits relative to bacteria, yeasts, and animals, but the amount of protein expression in plants is less. It is argued that editing 5'UTRs increases the amount of translated proteins. However, obtaining such 5'UTRs is difficult due to the cost, time and effort required in experiments. To solve this, we predict the amount of translated proteins by machine learning. In this paper, we propose a method, named “R-STEINER, ” that generates 5'UTRs that increase the amount of proteins of a given gene. The proposed process involves building a model for predicting the amount of translated proteins, generating 5'UTRs, selecting them and increasing the proteins according to the model. This method enables us to obtain 5'UTRs that increase the amount of translated proteins without real synthesis experiments, resulting in reduced cost, time and effort. In our study, we built a prediction model for Oryza sativa and synthesized the 5'UTRs generated by R-STEINER. We confirmed that the model can predict the amount of translated proteins with a correlation coefficient of 0.89.
著者
Akitoshi Okumura Takamichi Hoshino Susumu Handa Yugo Nishiyama Masahiro Tabuchi
出版者
Information Processing Society of Japan
雑誌
Journal of Information Processing (ISSN:18826652)
巻号頁・発行日
vol.25, pp.448-458, 2017 (Released:2017-06-15)
参考文献数
30
被引用文献数
3 4

This paper proposes a system of verifying the identity of ticket holders at large-scale events using face recognition, which is called Ticket ID System. Such a system has been required to prevent illegal resale such as ticket scalping. Since illegal resale is a critical problem for popular events in Japan, strict steps are followed for verifying individuals holding tickets at event venues by human visual inspection with ID cards. This task is time consuming for venue attendants. It is also stressful because ticket holders feel uncomfortable when being kept waiting. The problem in verifying ticket holders is how to simultaneously verify identities efficiently and prevent individuals from impersonating others at a large-scale event in which tens of thousands of people participate. Ticket ID system makes it possible to secure the identity of the purchaser and holder of a ticket by using a face-recognition system developed for tablet terminals. Ticket ID System was proven effective for preventing illegal resale by verifying 50, 324 attendees at a large concert of a popular music group. The average accuracy of face recognition was 90%. The average time for identity verification was 7 seconds per person including guidance to ticket holders, which decreased identity-verification time by 30% compared to using only human visual inspection as well as reducing the psychological workload of venue attendants. Survey results obtained from the attendees showed that 94.6% felt it provided more equity in ticket purchasing than methods used before, 83% felt it provided added convenience in verification, and 93.8% felt it would effectively prevent illegal resale.
著者
Toshihiro Ohigashi Shuya Kawaguchi Kai Kobayashi Hayato Kimura Tatsuya Suzuki Daichi Okabe Takuya Ishibashi Hiroshi Yamamoto Maki Inui Ryo Miyamoto Kazuyoshi Furukawa Tetsuya Izu
出版者
Information Processing Society of Japan
雑誌
Journal of Information Processing (ISSN:18826652)
巻号頁・発行日
vol.29, pp.548-558, 2021 (Released:2021-09-15)
参考文献数
19

In 2018, Takita et al. proposed a construction method of a fake QR code by adding stains to a target QR code, that probabilistically leads users to a malicious website. The construction abused the error-correction of error-correcting code used in the QR code, namely, the added stains induce decoding errors in black and white detection by a camera, so that the decoded URL leads to the malicious website. Also, the same authors proposed a detection method against such fake QR codes by comparing decoded URLs among multiple QR code readings since the decoded URLs may differ because of its probabilistic property. However, the detection method cannot work well over a few readings. Moreover, the proposed detection method does not consider the environmental or accidental changes such as sudden sunshine or reflection, nor recognizes the fake QR code as non-fake when the probability is low. This paper proposes new detection methods for such fake QR codes by analyzing information obtained from the error-correcting process. This paper also reports results from implementing the new detection methods on an Android smartphone. Results show that a combination of these detection methods works very well compared to when using only a single detection method.
著者
Yusuke Fukazawa Naoki Yamamoto Takashi Hamatani Keiichi Ochiai Akira Uchiyama Ken Ohta
出版者
Information Processing Society of Japan
雑誌
Journal of Information Processing (ISSN:18826652)
巻号頁・発行日
vol.28, pp.16-30, 2020 (Released:2020-01-15)
参考文献数
114
被引用文献数
4

Monitoring mental health has received considerable attention as a countermeasure against the increasing occurrence of mental illness worldwide. However, current monitoring services incur costs because users are required to attach wearable devices or answer questions. To reduce such costs, many studies have used smartphone-based passive sensing technology to capture a user's mental state. This paper reviews those studies from the perspective of machine learning and statistical analysis. Forty-four studies published since 2011 have been reviewed and summarized from three perspectives: designed features, machine learning algorithm, and evaluation method. The features considered include location and mobility, activity, speech, sleep, phone usage, and context features. Tasks are classified as correlation analysis, regression tasks, and classification tasks. The machine learning algorithm used for each task is summarized. Evaluation metrics and cross validation methods are also summarized. For those who are not necessarily machine learning experts, we aim to provide information on typical machine learning framework for smartphone-based mental state estimation. For experts in the field, we hope this review will be a helpful tool to check for potential omissions.
著者
Stephen J.H. Yang Owen H.T. Lu Anna Y.Q. Huang Jeff C.H. Huang Hiroaki Ogata Albert J.Q. Lin
出版者
Information Processing Society of Japan
雑誌
Journal of Information Processing (ISSN:18826652)
巻号頁・発行日
vol.26, pp.170-176, 2018 (Released:2018-02-15)
参考文献数
29
被引用文献数
18

With the rise of big data analytics, learning analytics has become a major trend for improving the quality of education. Learning analytics is a methodology for helping students to succeed in the classroom; the principle is to predict student's academic performance at an early stage and thus provide them with timely assistance. Accordingly, this study used multiple linear regression (MLR), a popular method of predicting students' academic performance, to establish a prediction model. Moreover, we combined MLR with principal component analysis (PCA) to improve the predictive accuracy of the model. Traditional MLR has certain drawbacks; specifically, the coefficient of determination (R2) and mean square error (MSE) measures and the quantile-quantile plot (Q-Q plot) technique cannot evaluate the predictive performance and accuracy of MLR. Therefore, we propose predictive MSE (pMSE) and predictive mean absolute percentage correction (pMAPC) measures for determining the predictive performance and accuracy of the regression model, respectively. Analysis results revealed that the proposed model for predicting students' academic performance could obtain optimal pMSE and pMAPC values by using six components obtained from PCA.
著者
Akira Tanaka Reynald Affeldt Jacques Garrigue
出版者
Information Processing Society of Japan
雑誌
Journal of Information Processing (ISSN:18826652)
巻号頁・発行日
vol.26, pp.54-72, 2018 (Released:2018-01-15)
参考文献数
30
被引用文献数
2

Our goal is the production of formally-verified pieces of low-level code. Low-level code is typically written in C, so as to enable efficient manipulation of data at the bit-level and easy access to built-in features of CPUs. Proof-assistants arguably provide the most rigorous approach to formal verification of computer programs. Unfortunately, they only allow for extraction of runnable code in high-level languages such as ML. Of course it is possible to embed C snippets into ML programs, but this results in a complicated extraction process and the performance of the output program becomes difficult to anticipate. In this paper, we propose a new code generation scheme for the Coq proof-assistant that directly generates provably-safe C code. It is implemented in the form of plugins. The generation of C source code is done by a plugin performing beforehand monomorphization of Coq programs. The correctness of monomorphization can be proved within Coq. Code generation allows for user-guided changes of data structures. It is therefore possible to do formal verification using proof-friendly data structures, while enjoying optimized C representations in the output code. In order to ensure the safety of this transformation, we propose a new customizable monadification algorithm in the form of another plugin. Using monadification, one can ensure by the insertion of the right monads the preservation of critical invariants, such as the absence of overflows or complexity properties. We provide several examples to illustrate our approach, including a realistic use-case: the rank algorithm from succinct data structures.
著者
Ryo Ishii Ryuichiro Higashinaka Koh Mitsuda Taichi Katayama Masahiro Mizukami Junji Tomita Hidetoshi Kawabata Emi Yamaguchi Noritake Adachi Yushi Aono
出版者
Information Processing Society of Japan
雑誌
Journal of Information Processing (ISSN:18826652)
巻号頁・発行日
vol.29, pp.30-44, 2021 (Released:2021-01-15)
参考文献数
30

Starting from their early years, many persons dream of being able to chat with their favorite anime characters. To make such a dream possible, we propose an efficient method for constructing a system that enables users to text chat with existing anime characters. We tackled two research problems to generate verbal and nonverbal behaviors for a text-chat agent system utilizing an existing character. A major issue in creating verbal behavior is generating utterance text that reflects the personality of existing characters in response to any user questions. To cope with this problem we propose use of role play-based question-answering to efficiently collect high-quality paired data of user questions and system answers reflecting the personality of an anime character. We also propose a new utterance generation method that uses a neural translation model with the collected data. Rich and natural expressions of nonverbal behavior greatly enhance the appeal of agent systems. However, not all existing anime characters move as naturally and as diversely as humans. Therefore, we propose a method that can automatically generate whole-body motion from spoken text in order to give the anime characters natural, human-like movements. In addition to these movements, we try to add a small amount of characteristic movement on a rule basis to reflect personality. We created a text-dialogue agent system of a popular existing anime character using our proposed generation methods. As a result of a subjective evaluation of the implemented system, our methods for generating verbal and nonverbal behavior improved the impression of the agent's responsiveness and reflected the personality of the character. Since generating characteristic motions with a small amount of characteristic movement on the basis of heuristic rules was not effective, our proposed motion generation method which can generate the average motion of many people, is useful for generating motion for existing anime characters. Therefore, our proposed methods for generating verbal and nonverbal behaviors and the system-construction method are likely to prove a powerful tool for achieving text-dialogue agent systems for existing characters.
著者
Christian Nitschke Atsushi Nakazawa Haruo Takemura
出版者
Information Processing Society of Japan
雑誌
IPSJ Transactions on Computer Vision and Applications (ISSN:18826695)
巻号頁・発行日
vol.5, pp.1-18, 2013 (Released:2013-01-24)
参考文献数
142
被引用文献数
8 30

The cornea of the human eye acts as a mirror that reflects light from a person's environment. These corneal reflections can be extracted from an image of the eye by modeling the eye-camera geometry as a catadioptric imaging system. As a result, one obtains the visual information of the environment and the relation to the observer (view, gaze), which allows for application in a number of fields. The recovered illumination map can be further applied to various computational tasks. This paper provides a comprehensive introduction on corneal imaging, and aims to show the potential of the topic and encourage advancement. It makes a number of contributions, including (1) a combined view on previously unrelated fields, (2) an overview of recent developments, (3) a detailed explanation on anatomic structures, geometric eye and corneal reflection modeling including multiple eye images, (4) a summary of our work and contributions to the field, and (5) a discussion of implications and promising future directions. The idea behind this paper is a geometric framework to solve persisting technical problems and enable non-intrusive interfaces and smart sensors for traditional, ubiquitous and ambient environments.
著者
Wataru Endo Shigeyuki Sato Kenjiro Taura
出版者
Information Processing Society of Japan
雑誌
Journal of Information Processing (ISSN:18826652)
巻号頁・発行日
vol.30, pp.269-282, 2022 (Released:2022-03-15)
参考文献数
26

User-level threading or task-parallel systems have been developed over decades to provide efficient and flexible threading features missing from kernel-level threading for both parallel and concurrent programming. Some of the existing state-of-the-art user-level threading libraries provide interfaces to customize the implementation of thread scheduling to adapt to different workloads from both applications and upper-level systems. However, most of them are typically built as huge sets of monolithic components which achieve customizability with additional costs via concrete C APIs. We have noticed that the zero-overhead abstraction of C++ is beneficial for assembling flexible user-level threading in a clearer manner. To demonstrate our ideas, we have implemented a new user-level threading library ComposableThreads which provides customizability while minimizing the interfacing costs. We show that the users can pick up, insert, or replace the individual classes of ComposableThreads for their own purposes. ComposableThreads offers several characteristic abstractions to build high-level constructs of user-level threading including suspended threads (one-shot continuations) and lock delegators. We evaluate both the customizability and performance of our runtime system through the microbenchmark and application results.
著者
Yuta Sugimoto Atusi Maeda
出版者
Information Processing Society of Japan
雑誌
Journal of Information Processing (ISSN:18826652)
巻号頁・発行日
vol.26, pp.335-344, 2018 (Released:2018-03-15)
参考文献数
21

Packrat parsing is a recursive descent parsing method with backtracking and memoization. Parsers based on this method require no separate lexical analyzers, and backtracking enables those parsers to handle a wide range of complex syntactic constructs. Memoization is used to prevent exponential growth of running time, resulting in linear time complexity at th cost of linear space consumption. In this study, we propose CPEG - a library that can be used to write parsers using Packrat parsing in C language. This library enables programmers to describe syntactic rules in an internal domain-specific language (DSL) which, unlike parser combinators, does not require runtime data structures to represent syntax. Syntax rules are just expressed by plain C macros. The runtime routine does not dynamically allocate memory regions for memoization. Instead, statically allocated arrays are used as memoization cache tables. Therefore, programmers can implement practical parsers with CPEG, which does not depend on any specific memory management features, requiring fixed-sized memory (except for input string). To enhance usability, a translator to CPEG from an external DSL is provided, as well as a tuning mechanism to control memoization parameters. Parsing time compared to other systems when parsing JavaScript Object Notation and Java source files are given. The experimental results indicate that the performance of CPEG is competitive with other libraries.
著者
Ayako Akiyama Hasegawa Takuya Watanabe Eitaro Shioji Mitsuaki Akiyama Tatsuya Mori
出版者
Information Processing Society of Japan
雑誌
Journal of Information Processing (ISSN:18826652)
巻号頁・発行日
vol.28, pp.1030-1046, 2020 (Released:2020-12-15)
参考文献数
42

Online service providers exert tremendous effort to protect users' accounts against sensitive data breaches. Although threats from complete outsiders, such as account hijacking for monetization, still occur, recent studies have shed light on threats to privacy from insiders. In this study, we focus on these latter threats. Specifically, we present the first comprehensive study of an attack from insiders that identifies the existence of a target's account by using the target's email address and the insecure login-related messages that are displayed. Such a threat may violate intimates' or acquaintances' privacy because the kinds of service accounts a user has implies his/her personal preferences or situation. We conducted surveys regarding user expectations and behaviors on online services and an extensive measurement study of login-related messages on online services that are considered sensitive. We found that over 80% of participants answered that they have sensitive services and that almost all services were vulnerable to our attack. Moreover, about half the participants who have sensitive services were insecurely registered on them, thus could be potential victims. Finally, we recommend ways for online service providers to improve login-related messages and for users to take appropriate defensive actions. We also report our responsible disclosure process.