With recent progress in lifelong map-learning as well as in information sharing networks, compact representation of a large-size landmark database has become crucial. In this paper, we propose a compact binary (.g. 32bit code) landmark representation by employing the semantic hashing technique from web-scale image retrieval. We show how well such a binary representation achieves compactness of a landmark database while maintaining efficiency of the localization system. In our contribution, we investigate the cost-performance, the semantic gap, the saliency evaluation using the presented techniques as well as challenge to further reduce the resources (#bits) per landmark. Experiments using a high-speed car-like robot show promising results.

抄録全体を表示

Raster maps are widely available in the everyday life, and can contain a huge amount of information of any kind using labels, pictograms, or color .g. However, it is not an easy task to extract roads from those maps due to those overlapping features. In this paper, we focus on an automated method to extract roads by using linear features detection to search for seed points having a high probability to belong to roads. Those linear features are lines of pixels of homogenous color in each direction around each pixel. After that, the seeds are then expanded before choosing to keep or to discard the extracted element. Because this method is not mainly based on color segmentation, it is also suitable for handwritten maps for example. The experimental results demonstrate that in most cases our method gives results similar to usual methods without needing any previous data or user input, but do need some knowledge on the target maps; and does work with handwritten maps if drawn following some basic rules whereas usual methods fail.

抄録全体を表示

We are developing an advanced Integrated Services Digital Broadcasting-Terrestrial (ISDB-T) system for the next generation of digital terrestrial television broadcasting. The advanced ISDB-T provides 4K8K terrestrial broadcasting service for fixed reception and 2K service for mobile reception simultaneously within one channel. New technologies such as Low-Density Parity-Check (LDPC) code are used for expanding the transmission capacity and for improving the spectral efficiency. The LDPC codes designed for the advanced ISDB-T have two code lengths and 13 code rates for each code length. The code length and code rate can be selected in consideration of the transmission latency requirement or the link budget. Meanwhile, although the LDPC codes have good bit error rate (BER) performance approaching the Shannon limit, a small number of error bits cause an error floor even if the E_s/N₀ is high enough. The error floor may cause serious issues such as block noise in video and mute in audio because broadcasting is a real-time service without any feedback. To deal with this problem, Bose-Chaudhuri-Hocquenghem (BCH) code is concatenated as outer code to the LDPC codes as inner codes. We conducted a simulation using a field programmable gate array (FPGA) instead of a computer to evaluate the BER performance. An FGPA simulation is 1000 times faster than a computer simulation, so the BER performance can be evaluated quickly with an adequate number of measurement bits. As a result, it was confirmed that LDPC codes perform as designed both in the water-fall and error-floor regions and that the BCH codes correct the small number of error bits after the LDPC decoder.

抄録全体を表示

Parsing expression grammars (PEGs) were formalized by Ford in 2004, and have several pragmatic operators (such as ordered choice and unlimited lookahead) for better expressing modern programming language syntax. In addition, PEGs can be parsed in a linear time by using recursive-descent parsing and memoization. In this way, PEGs have a lot of positive aspects. On the other hand, it is known that ordered choices defy intuition. They may cause bugs. This is due to a priority of an ordered choice. To avoid this, unordered choices are required. In this paper, we define a parsing expression grammar with unordered choices (PEGwUC), an extension of a PEG with unordered choices. By the extension, it is expected that a PEGwUC includes both a PEG and a context-free grammar (CFG), and this allows us to write a grammar more intuitively. Furthermore, we show an algorithm for parsing a PEGwUC. The algorithm runs in a linear time when a PEGwUC does not include unordered choice and in a cubic time in worst-case running time.

抄録全体を表示

Data stored in non-volatile memories may be destructed due to crosstalk and radiation but we can restore their data by using error-correcting codes. However, non-volatile memories consume a large amount of energy in writing. How to reduce maximum writing bits even using error-correcting codes is one of the challenges in non-volatile memory design. In this paper, we first propose Doughnut code which is based on state encoding limiting maximum and minimum Hamming distances. After that, we propose a code expansion method, which improves maximum and minimum Hamming distances. When we apply our code expansion method to Doughnut code, we can obtain a code which reduces maximum-flipped bits and has error-correcting ability equal to Hamming code. Experimental results show that the proposed code efficiently reduces the number of maximum-writing bits.

抄録全体を表示

Passive safety systems, which do not need external input to operate, are widely used to enhance the inherent safety. They are receiving increasing attention due to the remarkable advantages in the simplicity and reduction of human interactions. The main task of passive system reliability assessment lies in the estimation of failure probability taking various uncertainties into account. However, it is usually a challenging work based on the traditional Monte-Carlo method because repeatedly running thermal-hydraulics (.g., RELAP5) is required. Unfortunately, it is computationally impractical because a large number of simulations are needed. In addition, each simulation of such thermal-hydraulic code may take hours, the computational cost of which is prohibitively high. In order to address this problem, in the present work we propose an adaptive sampling method for Kriging metamodel. The proposed approach selects samples strategically based on the information from the previous iteration. The proposed method is tested with reference to one benchmark case and then applied to the reliability assessment of the passive residual heat removal system in an integral type PWR (IPWR200). Results indicated that this adaptive method decreases the calls of performance function to construct a Kriging model and improves the calculational efficiency to a great extent.

抄録全体を表示

Employing the vital statistics from January 1, 1979 to December 31, 1994 in Hokkaido Prefecture, Japan, we investigated the relationship between suicide (ICD 9 code, El 15) and days of the week. In one day 1.97 males and 0.98 females committed suicide on average. On Saturdays the number of suicides per day was the smallest. On Mondays it was the highest. When the days were classified into (1) a holiday, (2) the day before a holiday, (3) the day after a holiday (4) the day both before and after a holiday and (5) others, the rate of suicide was the lowest in the days before a holiday. In the days after a holiday, however, the rate was the highest. The same tendency was also noted when the subjects were classified into several subgroups from the viewpoint of ages, seasons or calender years. The time relation of holidays seemed to have something to do with the intention to commit suicide.
J Epidemiol, 2000 ; 10 : 317-320

抄録全体を表示

In general, we do not know which fault model can explain the cause of the faulty values at the primary outputs in a circuit under test before starting diagnosis. Moreover, under Built-In Self Test (BIST) environment, it is difficult to know which primary output has a faulty value on the application of a failing test pattern. In this paper, we propose an effective diagnosis method on multiple fault models, based on only pass/fail information on the applied test patterns. The proposed method deduces both the fault model and the fault location based on the number of detections for the single stuck-at fault at each line, by performing single stuck-at fault simulation with both passing and failing test patterns. To improve the ability of fault diagnosis, our method uses the logic values of lines and the condition whether the stuck-at faults at the lines are detected or not by passing and failing test patterns. Experimental results show that our method can accurately identify the fault models (stuck-at fault model, AND/OR bridging fault model, dominance bridging fault model, or open fault model) for 90% faulty circuits and that the faulty sites are located within two candidate faults.

抄録全体を表示

Hyperuricemia is defined as high uric acid levels within the bloodstream and is commonly associated with gout, type 2 diabetes mellitus, and kidney disease. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) are novel drugs that prevent glucose reabsorption; additionally, this drug has shown promising results in patients at risk of developing cardiovascular or renal complications by lowering uric acid levels. This study aimed to investigate the association between SGLT2i and hyperuricemia. Here, a self-controlled sequence symmetry analysis using the JMDC administrative claims database (January 2005 to September 2022) consisting of 12396 patients, who were newly prescribed both SGLT2i and hypouricemic agents, was conducted. Trend-adjusted sequence ratios (SR) at intervals of 6, 12, 18, and 24 months were calculated. Significant inverse signals across all intervals were observed between SGLT2i and hypouricemic agents, with the strongest effect observed in the 24-month interval [adjusted SR 0.52 (95% CI 0.49–0.55)]. Significant inverse signals were observed for each of the six types of SGLT2i across all intervals. This indicates that SGLT2i initiation may be associated with a decreased risk of hyperuricemia. Further investigation of the efficacy of SGLT2i is needed in hypothesis-testing designs such as cohort studies.

抄録全体を表示

北海道においてノビタキ Saxicola torquata は夏鳥であり,農耕地や自然草地において豊富に見られ採餌やさえずりにとまり場を利用する.(Nakamura et.al.1968,Greig-Smith 1983,Fujimaki 964,Fujimaki & Takami 1986).ノビタキのハビタットの植生について簡単に説明した論文はあるが,なわばり内の植生タイプ構成や異なった植生タイプの利用については記述されていない.この論文はノビタキの行動圏の植生的な特徴と,異なった植生タイプの利用について記述した.
調査は1990年に北海道帯広市の南部,札内川河川敷(42°52′N,143°11′N)で行った.調査地を25m×25mの区画に分け,各区画を植生の構造的特徴と優占した植物種に基づいて5つの植生タイプに分類した(Fig.1).タイプ1:背の高い植物(ススキ Miscanthus sinensis, ヨシ Phragmites communis, オオイタドリ Polygonum sachalinense)のバッチが低いイネ科草本(ナガハグサ Poa pratensis, オオアワガエリ Pheleum pratense)と混ざり合った植生,タイプ2:背の高い植物(セイタカアワダチソウ Solidago altissima, メマツヨイグサ Oenothera biennis, オオヨモギ Artemisia montana)が低いイネ科草本(ナガハグサ,オオアワガエリ)のなかに一様に点在している植生,タイプ3:ヤナギ科 Salicaceae の低木林.4:低いオオアワガエリ,5:高い植物(セイタカアワダチソウ,オオヨモギ,ススキ,ヨシ)が密生,巣を発見し,巣のあった区画の植生タイプを決定した.調査地にいた6つがい(A～F)と1羽のつがいになっていない雄について1回目繁殖の抱卵期に各雄を2時間追跡し,とまった場所を地図上にプロットし,行動圏に含まれる植生タイプを明らかにした.ノビキタによって頻繁に利用される植生タイプを調べるため,各繁殖ステージにおいて4:00から20:00まで2つがい(A,B)と1つがい(C)の雄の位置を1分ごとに地図上に記録し,さえずり回数を数えた.さえずり活動とその他の活動は分けて分析された.行動圏とソングエリアは最外郭を結んだ線で囲まれた区画と線上の区画を合わせたものとした.
巣があった区画はタイプ1が最も多く69.2%(13巣中9巣)を占めた.7つの行動圏ではどれもタイプ1あるいは2が主要な植生であった(Figs.2,3).雄3羽の行動圏サイズは繁殖ステージとともに変化したが,行動圏内の植生タイプ構成比に変化はなかった(Fig.4).ソングエリア内の植生タイプの構成比は行動圏内の植生タイプの構成比と類似し,繁殖ステージにともない変化しなかった(Fig.4).
雄のさえずり以外の活動のタイプ1における活動密度は,雄A,B,Cについてすべての時期で期待値(=行動圏内の1区画あたりの平均観察回数)と有意に異なった(Fig.5).雄Bは巣立ち期にタイプ1よりタイプ2と5を頻繁に利用した(Fig.5).雄Cは抱卵期にタイプ2と3を,巣立ち期にタイプ2をそれぞれ期待値より高く利用した(Fig.5).
さえずり活動では,雄A,B,Cは,雄Cの巣立ち期を除いてすべての時期で期待値よりも頻繁にタイプ1を利用した(Fig.6).雄Aは抱卵期にタイプ1よりもタイプ3においてより活発にさえずった(Fig.6).雄Cは抱卵期にタイプ1,2,3を,巣立ち期にタイプ2を期待値より多く利用した(Fig.6).
雌A,Bはすべての時期においてタイプ1を期待値よりも頻繁に利用した(Fig.7).雌Bは抱卵期と巣立ち期にタイプ3,4,5よりもタイプ2を頻繁に利用した(Fig.7).
本研究におけるハビタットの特徴は散在したとまり場という点において,他の地域のハビタットの特徴と類似した.活動における行動圏内の各植生タイプの利用を見ると,唯一タイブ4がどの個体によってもほとんど利用されなかった.タイプ4と他のタイプとの違いはとまり場の有無である.ノビタキは採餌やさえずりにとまり場を利用するので,タイプ4の利用が低いのはとまり場の不足によるものであろう.すべての個体がタイプ1と2をどの時期もよく利用した理由は彼らの採餌方法と関係があるかもしれない.彼らの採餌方法(とまり場から地面への飛び降り)はとまり場間の近い植生空間を必要とする.それ故,タイプ1と2は行動圏としてより好まれたのかもしれない.本研究の結果は,ハビタットとして好まれた散在したとまり場のある植生以外にも,林や高茎植物が密生した植物でもノビタキが活動することを示した.

抄録全体を表示

目的：自殺行為に関する研究では，主に3つの自殺企図手段分類方法が用いられている。すなわち，国際疾病分類第9版（以下International Classification of Diseases, Ninth Revision; ICD-9），飛鳥井分類（相対的危険群，絶対的危険群），そして侵襲度分類法（Non-violent群，Violent群）である。本研究は，これらの分類方法の違いが自殺企図手段と精神障害の関係に影響を与えるかを明らかにすることにある。対象と方法：救急搬送例のうち主要5精神障害（うつ病，双極性障害，統合失調症，適応障害，人格障害）と診断された169名を研究対象とした。3つの分類方法に準じた自殺企図手段と精神障害の関連について，対応分析法を用いて解析した。結果：ICD-9分類においては，E953（縊首，絞首，窒息）とうつ病およびE950（固体または液体による中毒）と適応障害は，それぞれ強い関連性があった。E957（高所墜落）は，統合失調症と弱い関係にあった。飛鳥井分類上の相対危険群は精神障害との関連性は弱かったが，絶対危険群は統合失調症と強い関係にあった。侵襲度分類においては，Non-violent群は双極性障害とViolent群は統合失調症とそれぞれ強い関係にあった。結語：自殺企図手段と精神障害の関係は手段分類法によりかなり異なっていた。

抄録全体を表示

Consider the source coding problem of finding the optimal code, in the sense of average redundancy, for the class of monotone sources with n symbols. The solution of this problem, known as the M code, is the Huffman code for the average distribution of the monotone sources. In this paper, we evaluate the average redundancy of the M code (on the class of monotone sources), and compare it with that of the Huffman code. It is demonstrated that for large n, although the M code is a fixed code (i.e., the codewords are independent of the symbol probabilities) for all monotone sources, its average redundancy is very close to that of the Huffman code. Moreover, it is shown that when n is large, the M code is a near-optimal code not only in the sense of average redundancy, but also the redundancy of almost all monotone sources. In particular, the redundancy of the M code converges in probability to its average value (≅0.029). As a result, the maximum redundancy of the M code, which can be as large as log n - log ln n, rarely occurs.

抄録全体を表示

Identification of priority areas for flood disaster risk reduction (FDRR) management is critical and often tedious to both planners and decision-makers. Requests for additional resources, infrastructures and capability enhancement may require a quantifiable basis for budget allocation. In Metro Manila, Philippines, flooding is a perennial problem, thus requires a regular assessment of FDRR management. This study provides a simple approach to address this requirement using a multi-criteria gap analysis method. This is demonstrated using the results of the assessment made by the local government units (LGUs) in Metro Manila at the aftermath of an extreme flood event in 26 September 2009. Results show that gaps ranging from very small to medium-scale exist in the management system of the LGUs. Serious attention must be given to land use planning and flood mitigation measures. Flood hazard mapping should also be a priority in most local government units. Efforts must also be made to improve flood warning dissemination.

抄録全体を表示

The aims of the present study were to investigate the effects of fenofibrate and bezafibrate on the risk of development of diabetic retinopathy (DR) in patients with type 2 diabetes and dyslipidemia. Japanese working age patients with type 2 diabetes and dyslipidemia were extracted from the Nihon University School of Medicine Clinical Data Warehouse. These patients were divided into three groups: control group (n=2549), fenofibrate group (n=40), and bezafibrate group (n=135). Multivariate logistic regression analysis was performed to assess the association between fibrates and the development of DR. After adjustment for covariates, fenofibrate showed no association with the risk of DR [adjusted odds ratio (OR), 0.160; 95% CI, 0.021-1.209; p=0.0758]. Bezafibrate also showed no association with the risk of DR (adjusted OR, 0.731; 95% CI, 0.411-1.299; p=0.2855). However, poor control of hemoglobin A1c (HbA1c ≥8.0%; adjusted OR, 3.623; 95% CI, 2.649-4.956; p<0.0001) and high low-density lipoprotein cholesterol (LDL-C ≥140 mg/dL; adjusted OR, 1.399; 95% CI, 1.013-1.932; p=0.0415) within the follow-up period of type 2 diabetes and dyslipidemia increased the risk of DR. Our results suggested that to prevent development of DR in patients with type 2 diabetes and dyslipidemia, controlling LDL-C levels as well as HbA1c levels under coexistence type 2 diabetes and dyslipidemia is more important than the selection of fibrate.

抄録全体を表示

Olanzapine is effective for schizophrenia management; however, it is contraindicated in diabetes patients. In addition, olanzapine is useful for treating nausea and vomiting, such as in the case of chemotherapy-induced nausea and vomiting (CINV). Therefore, we hypothesized that the contraindicated prescription of olanzapine likely occurs among cancer patients with diabetes, especially by non-psychiatric physicians. Hence, we conducted a nationwide survey to elucidate the situation of such contraindicated prescriptions and the associated risk factors. We extracted the data of patients who were newly prescribed olanzapine between April 2015 and March 2017 from the health insurance claims database developed by JMDC, Inc., Tokyo. The patients who were prescribed contraindicated olanzapine were defined as those who were prescribed olanzapine after a diagnosis of diabetes and diabetes drug prescription. In all, the data of 7181 patients were analyzed. We evaluated the proportion of diabetes patients who were prescribed contraindicated olanzapine from among those who were prescribed olanzapine. Furthermore, we investigated the background of patients who were prescribed olanzapine for information such as olanzapine prescribers and history of cancer chemotherapy. In all, 100 diabetes patients (1.39%) were prescribed olanzapine. In these patients, the frequency of olanzapine prescription was higher by non-psychiatry/neurology physicians than by psychiatry/neurology physicians (3.25 and 0.85%, respectively). Additionally, all olanzapine prescriptions in cancer chemotherapy-treated diabetes patients were issued by non-psychiatry/neurology physicians. Thus, our study revealed there were diabetes patients who were prescribed olanzapine. Additionally, olanzapine for CINV management was more likely to be a contraindicated prescription.

抄録全体を表示

An intercomparison exercise of radon, radon decay products and particle size distribution was carried out using the radon/aerosol chamber at National Institute of Radiological Sciences, 2002. Nine institutions participated in this exercise. Radon concentrations were first compared using a domestic ionization chamber, which was regarded as the primary standard equipment in Japan. Subsequently, several types of passive radon detectors were placed in the radon/aerosol chamber and their readings were compared with each other. Radon decay products concentrations were also intercompared, though the number of participants was small. After injection of Carnauba wax aerosols with the evaporation-condensation method, the particle size distribution of radon progeny was compared with three different sampling techniques: graded screen array, diffusion battery and cascade impactor. The present paper describes an overview of the experiment and the present status of correspondence on radon devices.

抄録全体を表示

To improve the operability for drivers with wider range of body size, the reach area of driver desks was measured under a simulated driving situation with a natural seat position in which shorter drivers were seated more closely to the desk than taller drivers. Simulated push buttons were used in exp.1 and actual ones in exp.2. The recommendable area in which over 80% of the participants evaluated the position of buttons as "not difficult to push" in exp.2 was larger than that in exp.1. It was considered that the area in exp.1 was applicable to buttons required for precise pointing, while that in exp.2 was to crude pointing.

抄録全体を表示