近年多発する豪雨や大地震によりため池堤体に関する被害が多数報告されている。貯水を目的としたため池堤体や河川堤防の土構造物内部では，水の浸透を長期間受けた結果，土粒子が間隙流体に取り込まれ，間隙を移動，さらには堤体外に流出する現象である内部侵食が発生する。内部侵食はその規模や発生形態によって分類されているが，そのうち，粗粒な土粒子が形成する間隙空間を細粒な土粒子のみが流出する現象はSuffusion（サフュージョン）と呼ばれ，地表面の変状を伴うことなく，潜在的に透水性の増加や地盤耐力の低下を引き起こしていることが分かっている。このようなサフュージョンが進行し続ければ，土構造物の安定性が経年的に失われる。しかし，それが土構造物に与える影響は元より，その発生や進行のメカニズム，発生要因についても十分に解明されていない。そこで，本研究ではサフュージョンがため池堤体土の強度特性に与える影響および流出土粒子粒径に着目したサフュージョンの進行メカニズムの解明を目的とした。 第1章では，研究背景，内部侵食の分類について整理した後，研究の位置付けと目的を述べた。 第2章では，サフュージョンに焦点を当てて，既往の研究で明らかにされたメカニズムや，地盤材料に与える影響について整理した。 第3章では，まず，ため池堤体土として用いられ，かつ，内部安定性の評価によってサフュージョンの発生リスクがあると判定された土試料を用いて，サフュージョンが強度特性に与える影響を調べた。セル室内で土粒子の流亡を伴う通水が可能となるように改良した三軸試験機を用いて，サフュージョンの有無による強度特性の変化を調べた。その結果，土粒子の流亡に伴う間隙比変化に対応しないピーク強度，残留強度の変化が認められ，せん断直前の間隙比が同じでも，サフュージョンの有無によって，その後の力学特性が異なることが分かった。ただし，侵食量は全体の0.7%以下と小さいため，土粒子は供試体内部を移動したものの，最終的に流出せずに滞留した細粒な土粒子の影響が強度変化に現れたものと考えられる。 第4章では，小規模な内部侵食のメカニズムにアプローチするために，地盤内部を通過し，漏出した濁水の濃度と濁度の関係に着目して，流出土粒子径の時間変化を調べる手法を考案し，予備検討を実施した。また，第3章で土粒子の流亡を伴う通水により得られた排水に対し，上記手法を適用した。その結果，侵食しにくい状況であると，流出する可能性がある土粒子の中から，粒径の小さい土粒子だけが間隙をくぐり抜け，径の大きな土粒子は排出せずに供試体内に滞留していることが推察された。 第5章では，サフュージョンを伴う一次元下向き通水実験を実施し，流量，土粒子の排出量および排水の濁度の三者の関係を詳細に調べた。その上で，第4章の手法を利用してサフュージョンの進行とともに変動する排出土の粒度組成を調べた。その結果，いずれの条件においても，流出境界面に設置したワイヤーメッシュの目開き径を通過できる流出可能成分の中からさらに粒径が小さな土粒子が選抜され，排出していることが分かった。また，サフュージョンの進行とともに，排出土の粒度組成が時間変化しており，その傾向が通水開始前の供試体の飽和度によって大きく異なることが分かった。実験終了後の供試体の粒度組成を調べたところ，高さ方向の流出可能成分の分布だけでなく，流出可能成分自体の粒度組成も不均一になっていくことが分かり，粒径の小さい土粒子ほど間隙での移動距離が長いことが推測された。 さらに，定水位条件下において上載圧がサフュージョン挙動に与える影響を調べた結果，動水勾配が大きい場合において，上載圧が大きいほどサフュージョンが発生しにくくなることが分かった。排出土粒子の粒度組成を調べたが，上載圧による違いはみられなかった。 加えて，動水勾配変動下におけるサフュージョンの進行について調べた。その結果，1回目の通水以降，土粒子の排出量は大幅に低下するが，動水勾配が上昇すると，土粒子の排出量が増加し，その状況は動水勾配を30回変動させてもなお継続した。流出土粒子の粒度組成を調べた結果，供試体に初めて動水勾配を与えた段階で，粒径が小さく流れやすい土粒子は既に抜けており，動水勾配の変動で流出する土粒子は，比較的径の大きな土粒子であることが分かった。 以上，サフュージョンによって流出する土粒子の粒径は，その発生を取り巻く条件や，進行時間によって変化することが分かった。サフュージョンの研究において，排出土の粒度組成は時間とともに変化する要素であり，サフュージョンの進行度を評価する項目になることが明らかになった。

睡眠は人体にとって不可欠な生理学的プロセスである。人は生涯の約３分の１を睡眠に費やす。睡眠時間と睡眠の質は、どちらも人間の健康にとって重要である。睡眠の質とは、睡眠プロセスがどれだけ安らかで回復力があるかを表すものである。80以上の睡眠障害が睡眠の質に影響を与えることが知られている。そのうち、睡眠関連の呼吸障害(SRBD)は、２番目の要因となっている。睡眠関連の呼吸障害は、睡眠中に呼吸の異常が発生する睡眠障害であり、睡眠中の異常ないびきや呼吸停止または異常に低い呼吸などによって血液中の酸素濃度が低下し、うつ病、心血管疾患、脳卒中、さらには死に至るリスクが高まる。したがって、睡眠中の呼吸のモニタリングと分析は、ヘルスケアにおいて益々重要視されている。 睡眠ポリグラフ(PSG)は、睡眠障害診断のゴールデンスタンダードとされているが、PSGは通常、医療技術者の監視の元で慣れない睡眠検査室で行われ、多くのセンサが着けられたため睡眠の妨げとなる場合も多い。本研究グループでは、一般家庭環境下で睡眠の質を常時にモニタリングする寝息呼吸音計測システムを開発している。本システムは、睡眠の邪魔にならないかつ簡便に終夜睡眠の呼吸音を高精度に計測することが可能である。本研究では、呼吸音の情報から睡眠の状態をより正確に分析するため、寝息呼吸音のパターン分類と呼吸の質を解析する技術の開発を目的とする。睡眠呼吸音には、正常な呼吸音といびき、異常な呼吸音といびきなど様々なバターンがある。これらのパターンを分類する方法、ならびに呼吸音から換気量を算出するアルゴリズムを開発することと、睡眠時無呼吸症候群の指数（AHI）を推定すること、さらに睡眠中の呼吸の質を評価することを試みる。 具体的には、寝息呼吸音のノイズをバンドパスフィルターで一部除去したのち、時間特性波形(TCW)を算出する。時間特性波形に基づき、解析に有効な呼吸信号を低レベルの信号から切り出し、呼吸フェーズと無呼吸または低信号にフェーズ分割する。次に、呼吸フェーズに対してメル周波数ケプストラム係数(MFCC)を求め、凝集型階層的クラスタリング(AHC)アルゴリズムを適用して、正常な呼吸/異常な呼吸と、正常ないびき/異常ないびき、また、寝返りなど呼吸に関連性の低いものに分類する。分類された呼吸パターンを30秒ごとに分析し、呼吸の換気量相対値を算出する。本研究で提案した技術と解析方法に対して、その有効性と正確性を検証するとともに、無呼吸症候群の指数（AHI）を推定する方法と、換気量を高中低レベルに換算し、睡眠中の呼吸の質を評価する方法を提案し、その有効性を検証する。 本論文は緒論・結言を含め７章から構成されている。 第1章では、本研究の背景と概要を述べる。 第2章では、睡眠時の呼吸音を分析するための信号処理技術と呼吸パターンの分類方法について述べる。睡眠時の呼吸音データには、歯ぎしりや体動による呼吸の乱れや周囲の環境ノイズなどが含まれることが多い。本章では、呼吸音を前処理してノイズをフィルタリングなどによる前処理を施した呼吸音信号に対して、時間特徴波形(TCW)と特徴モーメント波形(CMW)を算出し、吸気と呼気の分割を行う。各呼吸サイクルに対して、メル周波数ケプストラム係数(MFCC)を求め、特徴ベクトルとして、凝集型階層的クラスタリング(AHC)アルゴリズムへ適用して、通常の呼吸信号（正常呼吸と異常呼吸、正常いびきと異常いびき）と、寝返りや環境ノイズなど呼吸に関連性の低い信号に分類する信号処理技術を述べる。 第3章では、第２章で述べた技術を用い、睡眠時の呼吸音データを30秒ごとのフレームに対して、無呼吸、低呼吸、正常な呼吸、異常な呼吸、正常ないびき、異常ないびき、および寝返りなどのイベントに分類し、呼吸の状態を判別する方法を述べる。 第4章では、分類された異常呼吸音と低レベル呼吸音信号に対して無呼吸低呼吸Apnea-Hypopnea Index (AHI)の推定方法を提案し、PSGの診断結果と比較検討し、その妥当性と有用性を検証する。 第5章では、呼吸音から換気量の推定方法について述べる。正常の呼吸音は換気量に相関性が見られるため、本研究では、正常な呼吸と正常ないびきについては定量的に、無呼吸/低呼吸および異常な呼吸音については定性的に計算する方法を提案し、PSGの診断結果と比較検討し、その妥当性を検証する。 第6章では、応用展開として、本件で提案した呼吸音の分類方法を心音解析に応用する事例と、ブロックチェーン技術を用いた異なる施設や病院等で採集した聴診データを共有するためのデータ収集分散システムの構築について説明する。 第７章では、この研究の結論と今後の展望について述べる。

Innovation is the practical implementation of ideas that result in the introduction of new goods or services or the improvement in them (Schumpter, 1983). Innovation is closely related to invention as innovation is more on involving the practical implementation of a new or improved invention to make a meaningful impact in a market or society (Schumpter, 1939). On the other hand, innovative design is a process of identifying, pinpointing, and understanding the needs of the user or audience (Shaulis, 2021). Previously, Dixon (1966) defined innovative design as any design that is: new or different, or elegant or uses new ideas, or is an improvement over its peers. Once the market need has been identified, a solution can then be designed. In our proposed innovative design method, we introduced and investigated a method that is able to be applied in designing an intergrated system that could be a valuable solution to the society. This method starts with directly observe activities of things and real people in real trouble in the real field. Then, we think about the value of "I wish there were such things as…", visualize the story, draw a clear sketch to accomplish the story concretely. Next, we solidify the functions and specifications while investigating needs and competition. Then, we create a prototype that able to show and test your ideas, demonstrate to the people who need it, let them experience it, and gain feedback. Lastly, we evaluate the value of product design and development and plan methods for implementing it as an organization, and plan ways to improve and expand globally. All of the steps in this method are important for innovative design, however, in this research this time we focused on co-designing value, big idea, and considering as integrated steps for identifying latent needs of the consumers. It is because identifying needs is an important part in the product development process. Latent needs are those that many consumers recognize as important in a final product but unable to articulate in advance (Ulrich, 2015). The latent needs addressed in this study was focusing on identifying consumer requirements in product development in the innovative design method. The challenge in identifying latent needs is finding the method to elicit from consumers the needs which are not addressed by any inventors yet in the present market but would delight the consumers if delivered tomorrow. The purpose of this study is to propose and verify the method in the elicitation of latent needs from consumer needs by introducing a working prototype to the consumers, interviewing, and analyzing responses from the consumers. This research was conducted during the year the start of the COVID-19 pandemic. As the pandemic spread, most countries were forced to go into lockdown or declare an emergency state. The school was closed and business organizations needed to switch to working from home to prevent the spread. The parents were unable to work from home efficiently as they were worried their children will involve in dangerous incidents if the children were left by themselves. Based on this situation, this study was conducted in finding the latent needs of the parents, childcare workers, and children in order to assist them in going through their problems during this COVID-19 pandemic. The working prototype was used as material to prepare presentation slides for the consumers' interviews. The first presentation slides were focused on the background problems and ideas for the solutions while the second presentation slides provided consumers with a prototype and story of the product that was believed would be one of the solutions to the problems. Interviews were conducted after both slide presentations. Consumers' responses were obtained and interpreted into consumers' needs in terms of product functions. In the first study, consumers' interpreted needs from Problem-based interviews and Prototype and Story-based interviews were compared. Based on the results, latent needs interpreted from interviewees' responses and the categories of the needs obtained from the Prototype-based interviews are more than from the Problem-based interview. The latent needs that we were able to obtain from this research were for example, “The device is able to detect small changes in a child while watching he/she sleeping” which could lead into the prevention of unwanted incident such as sudden infant death syndrome (SIDS). This supports our assumption that showing working prototype-based materials with story descriptions can be effective in uncovering potential latent needs. In the second study, it is assumed that experience, empathy, and knowledge of working prototype is essential elements in product development, therefore, new additional guidelines which are “to write a statement with empathy”, “to write a statement as a designer”, and “to write a statement as someone with experience” were proposed during consumers' needs interpretation to see whether these new guidelines will influence the process of identifying latent needs of consumers. From the result, it is concluded that the number of interpreted needs increased when we applied the new proposed guideline. Although the number is small, the needs might not be interpreted if the new guidelines were not considered. We were also able to obtain a few important latent needs when we applied these new guidelines. A latent need collected from applying the guideline "to write a statement as someone with experience" is “The device is not for teaching love and humanity but for monitoring by watching facial expression, posture, and vital signals such as temperature and heart rate”. We could conclude that including these guidelines upon interpreting raw data from the consumers’ interviews might lead into discovering important and critical latent needs of the consumers. In the third study, a quantitative evaluation method for identifying latent needs was introduced. The consumers' interpreted needs were rated according to a basis of rating from the three perspectives of importance, latent-ness, and technological feasibility. The Degree of Latent Needs (DLN) was calculated by multiplying these three metrics. Based on the result for the average and variance of DLN mean value for each evaluator which is sufficiently small, it indicates that the basis of rating for three metrics of the DLN is effective. The results also indicate that the 20 highest DLN points of the interpreted needs contain attractive features in terms of design. However, we had gotten some pushback on the average of each interpreted need and its variance which indicates opposing opinions among evaluators. As it is possible that attractive needs are hidden and may lead to the discovery of latent needs through individual pinpoint interviews, the interviews with the minority evaluators were conducted. The interview results indicate that the latent needs with low DLN rates but valuable might be able to be discovered by conducting follow-up interviews such as “The device is able to recognize items (food or not) that a child wants to put in the mouth”. From the results in all three studies, we could conclude that a number of important latent needs are able to be elicited from consumers’ needs by applying the proposed method. In our fourth study, a decision-making method based on the patent analysis between the conceptual design stage and the prototyping stage in the innovative design method was introduced. Conducting a patent strategy was assumed to support how to select the right concept precisely. In this study, by conducting a patent search in this stage by the designer who understood best the product functions and working principles, a supporting method was introduced to assist the designer in their decision-making process. Based on the result, the method was able to observe whether there are dominating companies or not for our concept design. If there is a dominating company, the possibility of not being able to produce our concept becomes bigger. This method may be applied as an indicator to support decisionmaking in the concept design stage in the innovative design method, whether to proceed with the concept design or not and to reduce the possibility of product failure in the future. From the results of all the studies, we could conclude that these above methods may be applied as assistive tools to support designers’ understanding of consumers’ requirements and selecting the right concept design.

Aldosterone is a steroid hormone synthesized in the adrenal cortex and is part of the renin-angiotensin-aldosterone system (RAAS). It accelerates renal sodium retention and elimination of potassium through its action on the mineralocorticoid receptor (MR), and has a major role in regulating body fluid volume and blood pressure. Excessive secretion of aldosterone and activation of the MR cause cardiovascular inflammation, fibrosis and remodeling, and tubulointerstitial fibrosis and glomerular injury in the kidney. There are several reports on plasma aldosterone concentration (PAC) in healthy, chronic kidney disease (CKD), systemic hypertension, and chronic heart failure in cats and dogs. Measurement of urinary aldosterone/creatinine ratio has also been reported in cats and dogs. However, it has been suggested that measuring aldosterone in feline urine using the available methodology has limited or no utility in investigating feline hypertension associated with CKD. It may be important to evaluate PAC in cats and dogs with CKD associated with the activation of RAAS. On the other hand, angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers suppress the RAAS during hypertensive, renal, and cardiac diseases in cats. The Randomized Aldactone Evaluation Study in humans showed that the aldosterone antagonist, spironolactone, reduced the mortality of patients with chronic heart failure who received ACEI and loop diuretics. Spironolactone also reportedly reduced the mortality rate in cats with congestive heart failure secondary to cardiomyopathy. Another selective aldosterone antagonist, eplerenone, not only antagonizes MR but also blocks the nongenomic effects of aldosterone in vascular tissues not susceptible to spironolactone. These effects of eplerenone may be more effective than spironolactone in treating hypertension due to vasoconstriction. Although eplerenone reduces mortality and hospitalization in human patients with chronic heart failure, there are no available reports on eplerenone’s use in feline practice. Since elevated PAC is a risk factor for kidney injury in humans, and MR antagonists are beneficial in rodent models of CKD and human patients, it was hypothesized that if an elevated PAC is detectable in the early stages of the disease in cats, the use of eplerenone may prolong lifespan. However, the relationship between PAC and the survival time in cats and dogs with CKD has not been investigated. Therefore, this study aimed to investigate PAC in cats and dogs with CKD, and evaluate the influence of high PAC on the survival time of CKD animals and the effect of treatment with eplerenone in CKD cats with high PAC. In chapter 1, PAC in cats with CKD was investigated retrospectively, and the survival time of cats with high PAC was evaluated. Furthermore, the effect of treatment with eplerenone on survival time in CKD cats with high PAC was examined prospectively. The eplerenone study was conducted including both cats with CKD only and CKD cats complicated cardiac disease or systemic hypertension. The PAC was measured retrospectively in blood samples obtained from 156 client-owned cats that visited a veterinary hospital. The cats were designated into 2 groups: clinically healthy (n = 101) and CKD (n = 55). The PAC was measured by solid-phase radioimmunoassay. Median (minimum–maximum) PAC in healthy cats was 97 (10–416) pg/mL and the upper limit (95th percentile) was 243 pg/mL. In the CKD group, PAC [126 (10–981) pg/mL] was significantly higher than in the clinically healthy group. In the CKD group as classified by the International Renal Interest Society (IRIS) stage, the PACs were higher in IRIS stage 2 than in the healthy group. Similarly, PACs in IRIS stage 3 and 4 cats were higher than in the healthy group. In cats with CKD, the survival time of those with high PAC (n = 16) (> 243 pg/mL) was significantly shorter than that of those (n = 39) with normal PAC. In cats with high PAC and CKD, eplerenone administration (2.5 to 5 mg/kg body weight; n = 8) prolonged significantly the survival compared to cats not receiving eplerenone (n = 18). These results indicated that PAC could be a prognostic marker of CKD in cats and that eplerenone may prolong the survival in cats with CKD and high PAC complicated with cardiac disease or hypertension. In chapter 2, PAC in dogs with CKD was investigated retrospectively, and the survival time of CKD dogs with high PAC was evaluated. PAC was measured in blood samples obtained from 145 client-owned dogs. The dogs were divided into two groups: clinically healthy (n = 106) and CKD (n = 39). In clinically healthy group, median (minimum–maximum) PAC was 56 (10–250) pg/mL, and the upper limit (95th percentile) was 182 pg/mL. PAC (median 69 pg/mL; range 10–553 pg/mL) in CKD group was significantly higher than in the healthy group. In the CKD group as classified by IRIS stage, PAC (median 97 pg/mL) in IRIS stage 2 and 3 was significantly higher than in the healthy group. A significant positive correlation between PAC and IRIS stage was observed in CKD dogs, suggesting that the lower survival rate in high PAC group may be related to severity of CKD. In dogs with CKD, the survival time of those with high PAC (n = 10) (> 182 pg/mL) was significantly shorter than that of those with normal PAC (n = 24). These results suggested that high PAC might indicate shorter survival time in dogs with CKD. In conclusion, this study revealed that both cats and dogs with CKD had significantly higher PAC than clinically healthy animals. In CKD, the survival time of cats and dogs with high PAC was significantly shorter than those with normal PAC. The use of eplerenone also significantly prolonged the survival of cats with high PAC in CKD complicated with cardiac disease or hypertension. This study proposes PAC as a prognostic marker of cats or dogs with CKD. Eplerenone may be useful in prolonging cats’ survival with high PAC in CKD complicated with cardiac disease or hypertension. However, further study on PAC level in CKD progression and treatment response in a larger population may be required. This study provided new information on the relationship between PAC and the survival of cats or dogs with CKD, and the effect of eplerenone treatment for the survival time of cats with high PAC and CKD.

The objective of Chapter 1 of the present study was to evaluate the effect of heat-killed Lactobacillus sakei HS-1 (HK-LS HS-1) on the health and fecal bacteriological change of suckling Japanese Black calves as a supplement in milk replacers. To this end, they were randomly assigned to an HK-LS HS-1 supplement or a control without HK-LS HS-1 group in milk replacers. HK-LS HS-1 was administered from separation day to 3 weeks. Blood and fecal samples were examined. The result is glucose and vitamin A levels on day 7 were significantly higher in the supplement group than in the control group. No significant differences were observed in haptoglobin or serum amyloid A between the groups. The number of Escherichia coli in feces was lower in the control group than in the supplement group on day 21. No difference was observed in the number of Bifidobacteria, but that of lactic acid bacteria was significantly higher in the supplement group on day 21. The number of medications administered was significantly lower in the supplement group than in the control group during the experimental period. The results indicated that HK-LS HS-1 is potentially beneficial for improving intestinal microbes and reducing the number of medical treatments. In the second study, we evaluated the effects of supplementing cattle feed with difructose anhydride III (DFA III) by measuring urinary sterigmatocystin (STC) concentrations using 20 Japanese Black cattle aged 9–10 months from one herd. DFA III was supplemented for 2 weeks for 10 animals, and non-treated animals served as controls. STC concentration in the dietary feed was 0.06 mg kg−1(mixture of roughage and concentrate) at the beginning of the study (Day 0). The urine STC concentration was measured using liquid chromatography with tandem mass spectrometry 1 d prior to DFA 2 III administration, 9 and 14 d thereafter, and 9 d following supplementation cessation, concomitant with the measurement of serum amyloid A (SAA). The number of heifers in which STC was detected in the urine was low in the DFA III group compared to that in the control group on Day 9. After 9 d following supplementation cessation (Day 23), STC concentrations were significantly lower (P = 0.032) in the DFA III group than in the control group, although there was no difference in the number of heifers in which urinary STC was detected or in SAA concentrations between the two groups. Our findings demonstrate the effect of DFA III on reducing the urinary concentration of STC in Japanese Black cattle.