The electrophoretic display (EPD) is the main solution to electronic papers, but most of them can display the image or text in black and white particles only. The users may prefer the EPD showing multiple colors rather than the black/white content only. In this paper, we introduce the driving system for a color EPD, which is composed of three kinds of particles. The system aims at optimizing the visual quality based on a new driving waveform by equipping with an optimization method for color and tone reproduction. The experimental result shows that the proposed EPD driving system can display three-color pictures with promising visual quality.

Nowadays, rapid developments of Internet of Things (IoT) technologies have increased possibilities of realizing smart cities where collaborations and integrations of various IoT application systems are essential. However, IoT application systems have often been designed and deployed independently without considering the standards of devices, logics, and data communications. In this paper, we present the design and implementation of the IoT server platform called Smart Environmental Monitoring and Analytical in Real-Time (SEMAR) for integrating IoT application systems using standards. SEMAR offers Big Data environments with built-in functions for data aggregations, synchronizations, and classifications with machine learning. Moreover, plug-in functions can be easily implemented. Data from devices for different sensors can be accepted directly and through network connections, which will be used in real-time for user interfaces, text files, and access to other systems through Representational State Transfer Application Programming Interface (REST API) services. For evaluations of SEMAR, we implemented the platform and integrated five IoT application systems, namely, the air-conditioning guidance system, the fingerprint-based indoor localization system, the water quality monitoring system, the environment monitoring system, and the air quality monitoring system. When compared with existing research on IoT platforms, the proposed SEMAR IoT application server platform offers higher flexibility and interoperability with the functions for IoT device managements, data communications, decision making, synchronizations, and filters that can be easily integrated with external programs or IoT applications without changing the codes. The results confirm the effectiveness and efficiency of the proposal.

At present, web-client programming using HTML, CSS, and JavaScript is essential in web application systems to offer dynamic behaviors in web pages. With rich libraries and short coding features, it becomes common in developing user interfaces. However, the teaching course is not common in universities due to limited time. Therefore, self-study tools are strongly desired to promote it in societies. Previously, we have studied the programming learning assistant system (PLAS) as a programming self-study platform. In PLAS, among several types of programming problems, the element fill-in-blank problem (EFP) has been implemented for code understanding study of C and Java programming. In an EFP instance, the blank elements in a source code should be filled in with the proper words, where the correctness is checked by string matching. In this paper, we implement EFP for web-client programming in PLAS. In a web page, HTML and CSS define the components with tags in the document object model (DOM), and JavaScript offers their dynamic changes with libraries, which are blanked in EFP. Besides, a set of web page screenshots are given to help the solution. For evaluations, the generated 21 EFP instances were assigned to 20 master students in Okayama University. By analyzing their solution results, the effectiveness was confirmed for JavaScript programming learning.

Nowadays, C programming is essential for university students to study various programming languages, algorithms, and computer architecture. Previously, we have developed Java programming learning assistant system (JPLAS) for studying Java programming. JPLAS provides several types of exercise problems to cover different study stages, including the element fill-in-blank problem (EFP). An EFP instance asks students to fill in the blank elements in the given source code. The correctness of the answer is marked through string matching. In this paper, we study the EFP for C programming learning assistant system (CPLAS), by extending our works for JPLAS. To automatically generate a feasible EFP instance, the graph-based blank element selection algorithm is newly designed and implemented for C programming. For evaluations, we generate 19 EFP instances using C source codes for basic grammar concepts, and fundamental data structures and algorithms, and assign them to 42 students in a Myanmar university. The solving results confirm the effectiveness of EFP in detecting the students who may have difficulty in studying C programming and the hard topics for them.

A web-based Java programming learning assistant system (JPLAS) has been developed for novice students to study Java programming by themselves while enhancing code reading and code writing skills. One type of the implemented exercise problem is code writing problem (CWP), which asks students to create a source code that can pass the given test code. The correctness of this answer code is validated by running them on JUnit. In previous works, a Python-based answer code validation program was implemented to assist teachers. It automatically verifies the source codes from all the students for one test code, and reports the number of passed test cases by each code in the CSV file. While this program plays a crucial role in checking the correctness of code behaviors, it cannot detect code plagiarism that can often happen in programming courses. In this paper, we implement a code plagiarism checking function in the answer code validation program, and present its application results to a Java programming course at Okayama University, Japan. This function first removes the whitespace characters and the comments using the regular expressions. Next, it calculates the Levenshtein distance and similarity score for each pair of source codes from different students in the class. If the score is larger than a given threshold, they are regarded as plagiarism. Finally, it outputs the scores as a CSV file with the student IDs. For evaluations, we applied the proposed function to a total of 877 source codes for 45 CWP assignments submitted from 9 to 39 students and analyzed the results. It was found that (1) CWP assignments asking for shorter source codes generate higher scores than those for longer codes due to the use of test codes, (2) proper thresholds are different by assignments, and (3) some students often copied source codes from certain students.

Nowadays, indoor localization systems using IEEE 802.11 have been actively explored for location-based services, since GPS cannot identify floors or rooms in buildings. However, the user-side device is usually large and consumes high energy. In this paper, the authors propose a fingerprint-based indoor localization system using IEEE 802.15.4 that allows the use of a small device with a long-life battery, named FILS15.4. A user carries a small transmitter whose signal is received by multiple receivers simultaneously. The received signal strengths are compared with the fingerprints to find the current location. To address signal fluctuations caused by the low-power narrow-band signal, FILS15.4 limits one room as the localization unit, prepares plural fingerprints for each room, and allocates a sufficient number of receivers in the field. For evaluations, extensive experiments were conducted at #2 Engineering Building in Okayama University and confirmed high detection accuracy with sufficient numbers of receivers and fingerprints.